version,bump
IconPackHelper: Icon Mask / Back / Upon / Scale Support

Some icon packs cannot cover all the icons, so they may provide  something called "Icon Mask" or "Icon Back" or "Icon Upon" or scale value to make all the icons compatible with its style.

PS1 Add Support Icon Mask / Back / Upon / Scale (cherry-picked from CyanogenMod's Trebuchet repository)
PS2 Decouple Icon Mask and Icon Back 
PS3 Add support for icon packs with multiple icon masks/backs/upons (cherry-picked from CyanogenMod's Trebuchet repository)