CMake: don't treat warnings as errors in otprotob

The code is auto-generated by Google Protobuf.
opentxs: fix -Wunused-macros
Merge pull request #294 from toxeus/removeUnusedMacros

opentxs: fix -Wunused-macros
Make includes consistent: Google C++ style guide, no "../", etc.
cppcheck: update include folder.