Fixed some issues that may cause problems in future versions of Sketch.

Sketch is changing from JSTalk to CocoaScript for plugins. Mostly backwards-compatible, but some syntax differences.
Also fixed Draw Baseline Grid plugin in situations where nothing was entered by the user, and also User Input is now parsed
to a float, ready for arithmetic.
Fixed all plugins to be compatible with CocoaScript. Fixes #7.

Fixed bug in plugin that shrinks items to fit the horizontal grid.
Cleaned up some comments.
Renamed Resize to Column plugin to be more accurate (it actually aligns and resizes).