THRIFT-2107 minor Go generator fixes

Patch: Jens Geyer
THRIFT-2111: typo in php readme
Client: php
Patch: Jeremy Thomerson

Fixes type in php readme.
THRIFT-2112 Error in Go generator when using typedefs in map keys

Patch: Emir Habul
THRIFT-2017 Resource Leak in thrift struct under compiler/cpp/src/parse/t_program.h

Patch: kuldeep gupta
THRIFT-2105 Generated code for default values of collections ignores t_field::T_REQUIRED

Client: cpp
Patch: carl