-Added PowerManager

-Added BatteryEntity
-Fixed bugs in MultiblockStructure
-Added support for PowerManager in CubeGridEntity
-Added GetAssemblyType and GetMainGameMilliseconds methods to SandboxGameAssemblyWrapper

-Reworked a large portion of the BatteryEntity update code to fix some restrictions/bugs
-Added OnCubeBlockCreated and OnCubeBlockDeleted events
-Added ICubeBlockEventHandler to work with new cube block events

-Updated PluginManager to support new cube block events
Merge pull request #1 from SEModCommunity/master

Syncing with head fork