* Add php_generic_services option

* Generate PHP generic services

* Respect namespaces for generated PHP services

* Test PHP generated services

* Rename PHP generator service method doc comment function

* Correct phpdoc service method case

* Test namespaced PHP generic services

* Always use the FQCN for PHP generic service input/output

* Add generated_service_test to php test.sh

* Add php service test protos to CI

* Add php service files to php_EXTRA_DIST

* Use Interface suffix for php generic services

* remove pass by reference for php setters

* comments out memory leak test

Both native_slot_merge and native_slot_merge_by_array have no return
type declared. GCC implicitly uses int as return type in such cases,
however, these functions are actually void.

In the generated code of previous versions, each php field is given an
initial value. In c extension, it was assumed that the field order in
the generated code is consistent with upb fields order, so that the
correct initial value can be bound to the correct upb field. However,
this may not be true. The order of fields in generated code is decided
by proto compiler, while the order of upb fields is decided by the hash
function used in c extension.
This PR fixes the issue by reset the initial value at runtime.

* Add json encode/decode for php.

* Fix php conformance test on 32-bit machines.

* Fix conformance test for c extension.

* Fix comments

* adds PHPDoc @return and @param for getters and setters respectively

* addresses changes in PR review

* adds documentation tests

* Update php_generator:

- Prepend \ to names where required
- Remove <pre> tags
- Update protobuf field comments

* Updates class files with the protobuf changes

* Addresses review comments

* removes Protobuf Type line from PHP generated classes

* fixes phpdoc test

* adds array types to phpdoc

That implementation of json is not being used - this extension is using
a json encoder/decoder provided by 'upb'.

* Switch to addEnumType to fix fatal error

* Fixing more cases of HHVM incompatibility

* Updating tests to be hhvm compatible

* Fixing tests

* Fixing merge

* Don't use call_user_func, should hopefully fix tests

* Fixing spelling

* Fixing another misspelling in a test

* Fixing placement of append and kvUpdate functions

* Actually fix function helpers

* Remove double addEnumType. How did this ever work?

* Fixing a couple more tests

* Only use the setter if the return value isn't an object

That implementation of json is not being used - this extension is using
a json encoder/decoder provided by 'upb'.

Update commit id to upload latest composer.
Compile php with bc-math for future json support.

* Follows proper autoloading standards
 - Splits PHP classes in descriptor.php into separate files
 - Splits MapFieldIter and RepeatedFieldIter into separate files
 - Moves descriptor.php to Internal/functions.php
 - Moves all namespaced functions into Iternal/functions.php

* fixes Makefile.am for added php files

* [PHP] moves all functions to GPBUtil

* removes description.php from the makefile

* Add new file option php_namespace.

Use this option to change the namespace of php generated classes.
Default is empty. When this option is empty, the package name will be
used for determining the namespace.

* Uncomment commented tests

* Revert gdb test change

* Update csharp descriptor.

* Add test for empty php_namespace.

* Add compatibility test for php.

* Revert API incompatible change.

descriptor.proto uses proto2 syntax, which is not ready for external
usage. However, some proto3 files import descriptor.proto and cannot be
used. In this PR, all references (We cheated by only removing
extensions, which is enough for now. User should avoid using messages
defined in descriptor.proto as field type.) to content in
descriptor.proto are removed from generated files. Those that import
descriptor.proto can be used like other proto files.

Fix the bug by sharing the code for generating class name for both
message and enum.

This option will be prepended to generated classes of all messages in
the containing file.