Refactoring: FontMgr as a singleton instead of a global variable.
Merge pull request #62 from mariokonrad/refactor

Refactoring: FontMgr as a singleton instead of a global variable.
Implement pugiXML for improved navobj file performance
Port the possibility to turn off OpenGL completely from 3.2.2
Replace degree signs in the code with proper unicode encoded representation
Implement a hotkey (Ctrl+I) to hide/show GPS status indicator - FS#1001
Implement the possibility to drop waypoint on the current position of an AIS target from the target list/query dialog
Implement (M)ARPA radar targets tracking (TTM and TLL sentences) and AIS-like display, implement optional APRS position report tracking (uses WPL sentence) and AIS-like display (FS#964)