* Rename STRUCT_END to add FLATBUFFERS_ prefix, now FLATBUFFERS_STRUCT_END. Via running `ag -l STRUCT_END | xargs rpl STRUCT_END FLATBUFFERS_STRUCT_END`

* Rename MANUALLY_ALIGNED_STRUCT to add FLATBUFFERS_ prefix, now FLATBUFFERS_MANUALLY_ALIGNED_STRUCT. Via running `ag -l MANUALLY_ALIGNED_STRUCT | xargs rpl MANUALLY_ALIGNED_STRUCT FLATBUFFERS_MANUALLY_ALIGNED_STRUCT && cd tests && sh generate_code.sh`

* Rename DEFINE_BITMASK_OPERATORS to add FLATBUFFERS_ prefix, now FLATBUFFERS_DEFINE_BITMASK_OPERATORS. Via running `ag -l DEFINE_BITMASK_OPERATORS | xargs rpl DEFINE_BITMASK_OPERATORS FLATBUFFERS_DEFINE_BITMASK_OPERATORS`