Win/loss conditions based on logical expressions, yet another large
changeset:
- victory/defeat will be detected using triggered events
- vcmi will convert h3 conditions into set of triggered events
- it is possible to either change number of days without towns or even
remove this loss condition completely
- possibility of custom win/loss text and icons in pregame (no longer
connected to win/loss conditions)

Still missing:
- No interface to pass custom events/victory conditions into the game 
- AI would benefit from improvemets (handle all victory conditions,
select best one to fulfill)
- You have X days till defeat message still hardcoded to 7 days


git-svn-id: http://svn.code.sf.net/p/vcmi/code/trunk/@3686 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834