added comment operator (similarly to the delete/change operator) 

That was easier than I thought.  Just modified evil-delete slightly to create evilnc-comment-operator.  Takes a motion or text object and comments it.  Also yanks to clipboard in the process.

This allows for massive simplification of the evil keybindings:

    (define-key evil-normal-state-map "," 'evilnc-comment-operator)

since the previous functionality can be done via text objects/motions (see updated readme for details).

Known bugs:

1. If you try to uncomment a subregion of a comment, that subregion gets double-commented while the portions ahead of it get uncommented.