Event additions

[Vesku80]

Event system is a nice new feature, here are some requests for it:
- Decision feature similar to TOAW. You could for example use AP or VP to influence things on map or TB (drive to Suez, continued offence to Murmansk etc.). Even if my are examples aren't realistic, overall lack of manual trigger to start an event is the biggest drawback in the event system IMO.
- Ability to also move locked air units between TB and MAP.
- Some kind of variable system so with bigger investment you could for example have actual influence in strategic bombing (less frequent or damaging raids for example) or even partisan war.
- Event editor could also use easier way to test the system.