TODO
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User interface:
* Full 3D earth renderer (partially done)
* HUD to display text labels and icons (partially done)
  * Text label support
    * Bar with current geographical coordinates and statistics
* GUI (most probably GTK)

GoogleLayer:
* Refactoring of related stuff is needed (TileManager, Storages, ...)
* Implement fast indexed storage instead of current FilesystemStorage
* Multiple threads in KeyholeConnection (need support from libgefetch)
* Mipmapping
* Seamless tiles

Slave layers:
* GPS: Render path in lines, instead of HUD dots
* GPS: Path optimizer (convert strait line of points to 2 points)
* GPS: Interface to add muliple GPS entities from command line
* GPS: Auto reconnect to gpsd if connection is lost
* Grid: correct grid rendering
  * Render degrees for grid lines (via HUD)
* Anyone with any good layer ideas? Mail me (working layers are most
  welcome, of course:)
  * My ideas so far: SunlightLayer, TimezoneLayer,
    SatelliteCoverageLayer

Google Earth reverse engeneering:
* Support more data types (country borders, 3d buildings, topography)
* Correct authentication process (what we do now is pretty dumb)

Other:
* Windows port
* Test on other systems
* Test on 64 bit platforms (please send me a mail if you have 64bit
  machine)

Known bugs:
* Tile may be loaded twice?
* Tiles are sometimes stuck unloaded
* Timer is not threadsafe?
