Fixed a redefinition of Array.
Moved several constants to their proper files,
allowing multiple vars per scope.
Brought some constants from another file,
allowing for multiple vars per file in JSHint.
Done a first review of API doc-comments.
Made provisions for empty _inputNode for complex input elements
(ie. not input or textarea).
Added built-in support for a validator RegExp
(it was on the individual cell editors).
Dropped key input validation in favour of using the
valuechange event.  Will probably move this to a separate extension.