Added text -> StoreBlocks in preparation for transitions
Added transitions
* Current effects are: 
  - None: Same as current
  - ScrollDown: Old text moves down being replaced from new text from top
  - ScrollUp: Save as ScrollDown but opposite
* Added /supersigns change <name> <effect> <speed> <text>
  - Begins a transition effect to the specified text
* Added /supersigns cancel <name>
  - Cancels a transition
Added CoverUp + CoverDown transitions
Added RevealDown and RevealUp
Fixed issue with text being 1 block too wide