Switch to bufferevent
Merge pull request #14 from iclemens/bufferevent

Switch to bufferevent.
Cleaned up global namespace.
Cleaned up global namespace
Added frequency test
Return NAN if position is unavailable.
Empty line at end of file
Added pyc to gitignore.
Updated frequency test
Added common CMake file.
Add libevent include directory
Include common CMake file.
Include libevent directory.
Added const qualifiers. Removed obsolete RTC3D structs.
Cleaned up headers.
Using struct instead of casts.
Moved pointer arithmetic into message building functions.
Added const qualifiers.
Resolved conflicts