Fixed defect in cell highlighting code that allowed the selected cell not to
be highlighted.

Add ability to delet a selected effect using the right mouse button.
Merge branch 'master' of https://github.com/smeighan/nutcracker_c
Fixed bug that would crash if you deleted models during the xlights sequence
file loading.  Deleting in any other fashion then from the end of the list
would cause the crash.

convert the unmask of layers to occur using HSV instead of RGB.