Revert "Trying to get rid of `FMLCommonHandler.instance.getEffectiveSide` where possible, since it can apparently fail in some scenarios."

This reverts commit b3813bc4f563a4066fd79db1dad16db3673bb324.

And a few more related commits. Turns out this was caused by some Bukkit plugin, tho it is still unknown which one exactly.

Conflicts:
	src/main/scala/li/cil/oc/common/EventHandler.scala
	src/main/scala/li/cil/oc/common/component/TextBuffer.scala
Centralizing use of sided checks to make it easier to swap out for testing in the future, and added some hackiness to maybe make it more stable.
Some cleanup.
Merge branch 'OC1.3-MC1.6.4' of github.com:MightyPirates/OpenComputers into OC1.3-MC1.7.2

Conflicts:
	src/main/scala/li/cil/oc/common/block/Keyboard.scala
	src/main/scala/li/cil/oc/common/tileentity/Router.scala
	src/main/scala/li/cil/oc/common/tileentity/traits/TileEntity.scala