Fade: renamed Crossfade transition class because it now has more behavior
TransitionsExplorer: updated to use new Fade class that replaces Crossfade
ColorFade: added convenience functions for black and white, no longer defaults to black, since black has its own function
TransitionsExplorer: updated ColorFade example to show black and white, optimized Fade screen
Help: updated the transitions help file to include information about the new transitions, with a better tutorial for creating custom transitions (references #1046)