Removed dead code.
Merge pull request #263 from murrekatt/cleanup

Removed dead code.
cppcheck: update includes
Merge pull request #264 from toxeus/updateCppcheckIncludes

cppcheck: update includes
Removed SWIG defines from OpenTransactions.hpp because SWIG is not seeing this header so it should be fine.
Removed dead meat.
Merge pull request #265 from murrekatt/swig_cleanup

Swig cleanup
Removed unused function ProcessMessageOut(const char*, int32_t*).
Removed uses of u_header, removed, SetMessagePayload.
Deleted old code that dealt with sending unencrypted envelopes.
Removed unused includes.