Seperated out protobuf impl into wrapper classes.

Added Template information to RecordDecls and FunctionDecls.
Added Enum Information.
Removed decl parameters from wrapper class methods.
Omit processing RecordDecl forward declarations.

Test: header-abi-dumper -o example2.dump tests/example2.h -- clang -x
      c++ -I . -std=c++11 -I ~/android/aosp/external/clang/lib/Headers/

Change-Id: I4bd1eea25d00f2efc24ca38051a8d19a72c0fbb9