Minor improvements to tools blocks

* Uses the split block for word to list
* Uses the split block for sentence to list
* Removes the word to list block from the words and sentences library
(since it was promoted to the tools library)

The use of the split block makes the two blocks essentially a wrapper
function, and it should improve the performance of the two blocks when
used in projects. They function identically to the current versions.
Merge pull request #532 from cycomachead/tools-redux

Minor improvements to tools blocks