Remove unused method
Ensure that all combatants have a defined WinState at the end of the game
Fix OnObjective(Completed|Failed) not being called for secondary objectives
Make ScriptContext available in Actor- and PlayerProperty classes

Needed to return non-native types to Lua
Add OnCapture, OnAddedToWorld and OnRemovedFromWorld triggers to Lua API

This brings the new Lua API up to feature-parity with the old API in the
trigger department.
Add a number of small helper functions to Lua API
Add reinforcements functions to Lua API
Adjust gdi01 to use new functions
Replace explicit Dispose() calls with using statements in ScriptTrigger.cs
Merge pull request #6284 from obrakmann/gdi01-touchup

More Lua API enhancements