Added help blocks.
TODO: Set different colors for different libraries.
Added keys API.
Added VarArgsBlock.  So far, only tested with blocks-test.
TODO: Code generation and more testing.
Changed moveNumberedIndexBefore() to allow placing input at end of list.
Allow var args inputs to appear anywhere relative to other inputs.
Added two textutils blocks.
Changed how interpolateMsg() decides whether to inline inputs.
Combined some textutils blocks.
Added Vector API.