unsort table on row drag

resolves #134
ad-drop-leave method added to drag and drop

resolves #132
bower issue resolved
bower issue resolved
v2.0.6 released

- drag & drop on-drop-leave event added
- ad-drop-over class added to drop element for hover styling.
sort only if sortkey exists

seems to have problem with some version of angular
Merge pull request #135 from icyasblue/master

sort only if sortkey exists
Merge remote branch 'upstream/master'
fix for tablelite row drop button overlay