moved power logic up in the class hierarchy to allow other blocks than the power converter to accept energy from other mods - for now those other blocks are the computer case and the server rack. the converter still has its use when connecting to a remote power source, e.g.; added a bunch of checks in save logic to avoid errors when other mods call those methods client side (e.g. waila)
Merge branch 'master' of https://github.com/MightyPirates/OpenComputers into MC1.7

Conflicts:
	src/main/scala/li/cil/oc/common/tileentity/PowerConverter.scala
updated forge version