Nebula: Map-edge screen_loc anchors do not work (TOP, etc)

[out-of-phaze]

See ref:

The LEFT, RIGHT, TOP, and BOTTOM keywords (also TOPLEFT, TOPRIGHT, BOTTOMLEFT, BOTTOMRIGHT) can be used to anchor a screen object to the edge of the map control if the map is zoomed in so that some pixels are cut off. When you use these edge-alignment keywords, the icon size is taken into account, and the alignment of the icon changes to fit whichever edge you use. Because these keywords do not conform to the normal tile-based structure of the HUD, they can't be used for a range of tiles with the "to" format.

Currently these are just identical to NORTH/SOUTH/EAST/WEST.

[out-of-phaze]

Working on this, btw.

[wixoaGit]

As of #2106 these anchors use icon size instead of tile size. The other half of fixing this issue would be to have the icons stick to the edge of the visible map when the map's container is smaller than the map itself.