Merge pull request #200 from Zverik/master

Leave at least 3 points in a polygon
Coding style.
Bump to dev version
Update build
EditToolbar now sets it's state correctly

Properly determines if it has layers, and then sets the button's disabled class.

fixes #202
Merge pull request #203 from joeybaker/patch-1

EditToolbar now sets it's state correctly
Remove unused toggleClass and code style fixups.
Update changelog.
Update build
Fix virtual nodes position (#207)