[uniques] Make uncaptured and unvisited portals stand out more

Use lower opacity for captured portals. 
Make the border a bit thinner to show more of the highlight color.
This way it is easier to pick out the uncaptured and unvisited portals on a dense map.

See preview:
http://gfycat.com/ThirdCalmDragon
http://gfycat.com/WebbedEntireGallowaycow