Significantly bugfixed persistence and link adding/removal. Not yet fully there, but getting closer to release

Cleaned up communication structure significantly, should now be easier to add new links. Signal bytesReceived(link, QByteArray) is now only way to pass on newly received data

Currently testing parameter write, close to completely working, created beta release binary from this state

Pushed parameter interface forward, now receiving of onboard params works, working on display and writing

Switched from flite for speech on the Mac to built-in MacOSX speech synthesizer. Fixed build system for 64-bit builds (using official SDL.framework, and Qt frameworks).