mixer fix
Added start of shortcut window
Added the smaller shortcut functions
Added missing functions and window_shortcut_change
Moved mini window into seperate file. Fixed all bugs
Added the ability to read the current keyboard assignment
Merge pull request #508 from zsilencer/master

mixer fix
Merge pull request #509 from duncanspumpkin/window_shortcut

Window shortcut
Merge branch 'master' into reorganise-src

Conflicts:
	projects/openrct2.vcxproj
	src/interface/window.h