Fixed compilation and design issues for OS X:
* OS X uses Unix-style openCV build rules
* MapManager and DisplayTextureManager instances are created after the OpenGL context has been created
* QString can not be initialised to NULL in gcc
* Add gcc flag to remove a warning about the order in which member variables are initialised
* Removed font-size from aboutdialog text
* Resized patternsdialog
* Resized unitmapdialog