refactoring: removed unused or obsolete tests and cleaned up some imports from commun.py
refactoring: removed servermsg.py and the Sequence class
completely removed recorded speech
refactoring: removed commun.py
refactoring: removed g.py (global variables moved to clientmedia.py and clientmediascreen.py)

Some changes were done in the process:
- Windows: default audio buffer is 1024 instead of 3*1024 (was probably 4*1024)
- removed graphic console for stdout and stderr
- Ctrl+F2 now works in menu mode too (toggle display)
refactoring: extracted several modules from worldunit.py (orders, abilities, upgrades); added is_teleportable variable
bug fixed: a unit in defensive mode didn't take allies into account before deciding to flee or not