* Add '-fsanitize' optional flags to flattests and flatc targets

Control: -DFLATBUFFERS_CODE_SANITIZE=(ON | OFF | "=memory,undefined")
Travis-CI: building with -DFLATBUFFERS_CODE_SANITIZE=ON

* Fix -pie flag

* Cleanup

Change-Id: Iff00a48b370f45f80d68e6c6929483d608ce1885

Change-Id: Id8c373b0f77d9a0f4922257339abb4e01e06c2d4

* clean up unneeded outer rust gen-snippet

* update generated rust file

Give the vtable offset enum inside each table the name
"FlatBuffersVTableOffset" and base type voffset_t so it can be used as a
dependent type in IsFieldPresent. This makes that function slightly
safer since it prevents calling it with arbitrary, non-table types.
Now, the only way to use IsFieldPresent incorrectly is to create your
own type which does not inherit from flatbuffers::Table but has a
dependent voffset convertible type "FlatBuffersVTableOffset".

* Add fuzzer test for scalar numbers in json. Grammar-based regex used to check correctness.

* Fix conversation

* call reflection code generation from tests

This simplifies instructions to contributors so they don't forget to update
reflection code.

* add error handling to generate_code scripts

Let them propagate their errors instead of swallowing them so they show
up when called in CI.

* apply editorconfig to shell scripts

* use ordered map in dart codegen

Using an unordered map in the codegen can lead to spurious diffs in the
generated dart code.

* add CI check for generate_code being run

* update reflection_generated.h

* disable diff-check for monster_test.bfbs

Work around #5008.

* forbid enum values that are out of range

Enum values that are out of range can lead to generated C++ code that does
not compile.  Also forbid boolean enums.

* update enum and union documentation slightly

* Efficient conversion of FlatBufferBuilder to grpc::MessageBuilder

* Added a variety of tests to validate correctness of the MessageBuilder move operations.
Disable MessageBuilder half-n-half tests on MacOS.

* Fix failing Android build

* Generalized the MessageBuilder move constructor to accept a deallocator

[Python] Fast serialization of numpy vectors (#4829)

* Use Go bool type for bool fields, and store non-default bool field to test data

Fixes #4857.

std::function makes code harder to debug because it requires stepping
through a separate destructor and call operator.  It's use unnecessary
in the Parser since the functions taking functors are private and are
only used within idl_parser.cpp.  Therefore the definitions can stay in
idl_parser.cpp as well.  Only care must be taken that the definitions
appear before use but that's already true and all compilers will
complain equally if it get's violated.  This change might also improve
performance since it might allow inlining where it wasn't possible
before but I haven't measured that.

* Refactoring of numbers parser

More accurate parse of float and double.
Hexadecimal floats.
Check "out-of-range" of uint64 fields.
Check correctness of default values and metadata.

* Remove locale-independent code strtod/strtof from PR #4948.

* small optimization

* Add is_(ascii) functions

* is_ascii cleanup

* Fix format conversation

* Refine number parser

* Make code compatible with Android build

* Remove unnecessary suppression of warning C4127

Print a slightly better error message when a TestError fails.

* Add @javax.annotation.Generated to generated flatbuffer Java types.

* Updating test goldens.

Make an out-of-bounds check for enum values before using them to index the
names array.  For consistency with non-sparse enums an empty string is
returned.

Fixes #4821

Fixes #4930

Reference::As<> was needlessly mutable wich made them
less safe and harder to use

armeabi support was removed from the Android NDK so we should no
longer build it.  Since this fixes the Android build failures this
commit also re-enables Travis Android builds.

While re-enabling Android builds, some recent changes broke C++98
support so this fixes those issues as well which include:
- Conditionally compiling use of move constructors, operators and
  std::move.
- Changing sample to use flatbuffers::unique_ptr rather than
  std::unique_ptr.

Finally, added the special "default_ptr_type" value for the
"cpp_ptr_type" attribute.  This expands to the value passed to
the "--cpp-ptr-type" argument of flatc.

In Javascript, generate bidirectional mappings for enums, between Name: Value and between Value: Name. (#4960)

* Fix recursion counter check. Add control to override depth of nested objects.

* Change if-condition to `>=`

Change-Id: I9a6256d90ea800834a887afdcf888df412018933

Change-Id: I751f3bbd85eb1b521e1533c68f95442af0d18b8a

This allow recycling/pooling instances without leaking ByteBuffers, by
providing a mechanism to reset instance to newly constructed state.

* Assert tests on the first failure. Disable pop-up message box on assertion.

* Fix format and code style

* Move MSVC dependent code to ifdef

As recommended by https://golang.org/pkg/cmd/go/internal/generate/:

  To convey to humans and machine tools that code is generated,
  generated source should have a line early in the file that
  matches the following regular expression (in Go syntax):

        ^// Code generated .* DO NOT EDIT\.$

Download and build with a known grpc version

With the old-style code, the test fails with a borrow-checker error:

```
  #[inline]
  pub fn name(&'a self) -> &'a str {
    self._tab.get::<flatbuffers::ForwardsUOffset<&str>>(Monster::VT_NAME, None).unwrap()
  }
```

```
error[E0597]: `e` does not live long enough
   --> tests/integration_test.rs:273:57
    |
273 |         let enemy_of_my_enemy = monster.enemy().map(|e| e.name());
    |                                                         ^      - `e` dropped here while still borrowed
    |                                                         |
    |                                                         borrowed value does not live long enough
274 |         assert_eq!(enemy_of_my_enemy, Some("Fred"));
275 |     }
    |     - borrowed value needs to live until here
```

* Add more apis to query vector types from a reference

https://github.com/google/flatbuffers/issues/4818

* changing order of apis

* another reordering

* removed vector element type api as not needed as for now