new edge3x scaler implemented, diff attached
I've added yet another 3x scaler filter. It looks visually sort of in between advmame3x and hq3x, with a good balance between sharpness and blurriness. I'll attach a diff for all the files currently in the src, then follow up with another attachment of the common/scaler/edge3x.cpp file. If someone can come up with a better name for the filter than Edge3x, that would be welcome :)
Ticket imported from: #1061407. Ticket imported from: patches/472.