cursors return nextState after commit
onChange returns new cursor (for double setState problem)
Extract common cursor functions into a separate file
Add ReactCursor, which leverages react's update addon for working with immutable data

This also introduces react as a project dependency.
Introduce underscore as a project dependency
Add hashString and hashRecord to CursorFunctions
Make ReactCursors that share paths also share onChange handler references
Ignore IDEA project files
Add underscore stub to almond-end.txt