add support for different debuggers' dialects

IDA's side Syncplugin.py is now able to speak (send commands) to
different debuggers (ex: Windbg or GDB).
GDB plugin reworked

- support gdb<->ida dual way communication channel
- support for Python 3 for last gdb builds (7.7+ ?)
Merge pull request #1 from quarkslab/master

pull req