Blender Git Loki

* Alt-key smooth and Shift-key invert are now properly done as modifiers to LMB sculpting. This means they can be remapped to other buttons (for example, putting "Alt-smooth" on the RMB or whatever).

** Serious downside is that it is now not possible to do invert or smoothing in the same stroke. You have to let the mouse button go and start a new stroke to change the mode.

** Minor downside is that the cursor no longer changes when you change the mode of the stroke by pressing the key.

I believe these downsides will be resolved and that the benefit of having a proper re-mappable operation outweighs the downsides.

* Cleaned up the properties that appear in the key map configuration for LMB, LMB-Shift, and LMB-Alt. Only "ignore background click" was actually supposed to be there.

* I quieted the warnings generated by paint_image.c and in the process found an error where a result was supposed to be rounded to the nearest integer but instead was always truncated.

* I quieted a warning about signed/unsigned mismatch, it may have been better to actually fix that one.