imageoverlay: Create fiter to overlay an image

Change-Id: Ic6c1bed34f0a230f6cbe9a580986452142492d14
faceoverlay: Create a filter to overlay images to faces

Change-Id: Ifcee6df1f48b3393468001ea303950e9b1285834
imageoverlay: Allow to set the overlay image from file or url

Change-Id: I107a8f5ed116dd6115d54902d101f6bf2e3aa63a
imageoverlay: Draw a circle around the face if the image is not loaded

Change-Id: I0dfc523909c122c86bacf7e492b4b0885ceca953
imageoverlay: Handle alpha channel in  images

Change-Id: Ie01d643bd4f5bc2e852f5b1e4195d02c85297965
imageoverlay: Change image modifiers parameters from int to double

Change-Id: I5911c90c8f04d824008064964e8e3946d2acbeeb