WowAce

Hendrik Leppkes:
    - Removing an icon doesn't need a full update
    The removed icon is simply hidden, existing icons are not affected
    otherwise.
    - Removing icons should hide and remove them from the active list as well
    - Hide minimap pins when they move out of the active list
    - Add a function to set the active minimap object to position pins on
    Fixes ticket #2
    - Hide minimap pins when removing them
    - Factor the terrain match pattern into an upvalue constant
    - Apply map transforms to floors as well.
    No map is currently known to actually use this, however.