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