Touch support

Changed things for better usability on touch devices.
Sadly I could not test the changes with my ipad by now (I am not faimiliar with gh-pages... sry).
I know that there is still some issue with the plugin-control-icon on the ipad (since I did not change anything here... however, this is not related to the retina display (on a retina macbook pro everything looks like it should).

Here is a short overview of what has been changed (for more detail see single commits):
 - No close button aynmore (replaced by next button)
 - No toggleSize button (controls is always full size)
 - No mouse events anymore (text is shown at the bottom of the map after activating the plugin or clicking the next button)
 - StopPropagation for events (caused problems in my webapp)
 - z-index set to 1000 (so editor is above leaflet controls)
 - fixed mahor problem in bower.json (missing comma -> broken syntax)
 - added support for geoJson layers (and added test layer to index.html)
 - added support for layerGroups (changing all markers in one layergroup... introducing useGrouping flag)
 - added todo in StyleForms.js (regarding grouping)

I think that I covered all relevant changes ;-)
Merge whatever you like (or even all my changes :-))... I really hope that you like some of my ideas :smile: