[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

* Fixed MakeCamelCase behavior when supplied Upper_Camel_Case,
snake_case and UPPERCASE strings.
* Modified the rust integration test to reflect changes.

* Add FlatBufferBuilder move semantics tests to main

Do not eagerly delete/reset allocators in release and release_raw functions
Update android, vs2010 build files
New tests for various types of FlatBufferBuilders and move semantics

* Improve test failure output with function names

* Add operator== for c++ genated code

New "--gen-compare" option for flatc to generate compare operators. The operators are defined based on object based api types.

Inspired by issue #263.

* Improve compare operator for c++.
Thanks for the code review.

- Improve robustness against future schema extensions
- Code style
- Fix --rust generation in generate_code.sh

Change-Id: I9b0664a3bde44a4ee44ef0fd117d0e4bedc132d9

Different implementations of std::hash kept littering commits with
namespace changes.

Change-Id: Ic2d4fdcd76f8fef9802bc1572eb74ae7427085e3

Change-Id: Ic97f5b50fa191f967672c404f737d302462fc6ac

* C# support for directly reading and writting to memory other than byte[].  For example, ByteBuffer can be initialized with a custom allocator which uses shared memory / memory mapped files.

Public access to the backing buffer uses Span<T> instead of ArraySegment<T>.

Writing to the buffer now supports Span<T> in addition to T[].

To maintain backwards compatibility ENABLE_SPAN_T must be defined.

* Remove usage of expression bodied method so that ByteBuffer can be compiled with older version of C#.

This adds the ability to dispose unused buffers or to return them to an object pool