UI cleanup:

New layer in texture painting will now allow entering image parameters,
similar to new image.
Change to previous commit, allow tweaking name at creation time.
Fix minor issues from recent commits.

* Clone from layer UI not working
* Get trash color when entering texture painting for the first time
Move stencil options to own panel under layer tab.
Fix T41160: Rendering duplifaces crashed blender (cycles)
Code cleanup: ghost style
Fixes:

* Crash with image drag'n'drop
* Drag'n drop color to paint 2d canvas not working
* Change "Layers" to "Slots" to appease purists.
Fix T40925: Scene gravity hard limited

Remove hard limit, but keep soft limit because it might cause some
negative effect on physics stability.
Correction to recent rip-tear
initial intersect code
initial isect
intersection script
test vert intersection
check for intersections where no new verts are added first
minor fixes
WIP
add vert-edge check
Print info
De-duplicate - dont add same verts to edge multiple times
Dissolve