Image densities

@karllindmark this is just temporary pull request

 • Updated Android target sdk to 5.0 and build tools to 21.0.1
 • Density images provided for weapon & vehicle statistics, unlocks, assignments and awards (medals only)

Have go and let me know what you think

My observations:
 • Weapons, vehicles looks good
 • Unlocks image size is good but layout need update to get check/tick sign I guess above right of unlock item
 • Assignments and awards looks good but large so I suggest resizing. According to dimensions from layout it was set to 142dpi. As this is little irregular size I used 144dp, which makes mdpi as 144px, hdpi as 216px, xhdpi as 288px and xxhdpi as 432px. The other layouts are using with of 128dpi so I can try to use this on awards and assignments.