Made windows window borders c_white like their linux equivalents.
Close overmap with 'm' key.
Merge branch 'master' of https://github.com/TheDarklingWolf/Cataclysm-DDA
Merge branch 'master' of https://github.com/TheDarklingWolf/Cataclysm-DDA
Added a new variable TARGETSYSTEM, which is set to WINDOWS or LINUX according to
the desired system.

Calling make without parameters automatically sets the target to Linux.

Added a section for global settings for Windows and Linux.
Linux only needs -ncurses.
Windows needs additional stuff.

Relaxed the cross-compile target. The cross-compiler prefix now only needs to
contain mingw32, as there are many different versions out there.
Merge branch 'master' of https://github.com/TheDarklingWolf/Cataclysm-DDA
Fixed broken overmap Note blinking.
Signed the License signoff.
Fixed construction menu lettering.
Add overmapbuffer class for caching overmaps.
Integrate overmapbuffer as the cache of overmaps.
Merge branch 'master' of https://github.com/TheDarklingWolf/Cataclysm-DDA
List Item tweaks.
Redraw terrain after closing +/- priority popup.
Display Reset text when filter is applyd.
Allow resetting priority with empty text.
Full height bionics window
Fix unloading a weapon from the inventory screen, skip some deletion/creation
Fix artifact armor (fix incorrect superclass constructor call)
Add a clear method to overmapbuffer and call it when resetting the world.
Bugfixes of the Day.
Update changelog with the rest of the 0.5 changes
Add a "highlights" section to the 0.5 changelog