Add Trapdoor Functions to cWorld and fix Trapdoor Redstone Bugs
More documentation (thanks to madmaxoft) and use GetBlockTypeMeta
Add cancelling to WeatherChanging event.
Merge pull request #746 from Howaner/Slabs

Add Trapdoor Functions to cWorld and fix Trapdoor Redstone Bugs
Fixed previous weather changes.

cWorld::GetDefaultWeatherInterval() returns -1 for unknown weather.
Fixed an assert in map-loading.

The maps were loaded too soon, the world wasn't initialized yet.
cLuaState: Made public the GetStackValue() functions.
Manually exported cCompositeChat modifiers.

This adds chaining support to them. Fixes #755.
Debuggers: Added simple test for cCompositeChat.
Fixed some gcc warnings in Defines.h.