osm-gps-map example applications

Run C and Python demos from this directory (examples) so they find mapviewer.ui
and poi.png. 

If running uninstalled, you probably need to tell GObject introspection where 
to find the bindings. Do the following from the example directory:

    export LD_LIBRARY_PATH=../src/.libs/
    export GI_TYPELIB_PATH=../src/

 * ./mapviewer
   C based demo app with many options. See '--help' for a list of options.
   --editable-tracks makes the right-click track draggable.
 * ./polygon
   This example demonstrates editable polygons. Vertices can be dragged. 
   Clicking mid-points divides the line and creates another vertex.
 * ./editable_track
   One editable track. Same degree constructor as polygon.
 * ./mapviewer.py
   Python version of the C demo app, with examples showing how to do custom
   layers: DrawLayer class for cairo overlay, GPS, programmatic image_add,
   and track_add.
 * ./mapviewer.js
   Javascript example using seed + gobject-introspection.

Examples for drawing on the map:

 * Double-left-click places a GPS point (blue ball+random heading).
 * Double-right-click (or Ctrl+double-left) adds points to tracks.
   Triple right click clears the track (a new empty track stays on the map).
   This shows the use of track_add, add_point and track_remove
 * Double-middle-click (or Shift+double-left) adds a marker via image_add.
   Python: poi.png by default, or uncheck "Use poi.png for markers" to
   paint a cairo star (programmatic pixbuf). C: poi.png, or a cairo star
   if that file is missing. Triple middle click removes the last image.
 * DrawLayer in mapviewer and mapviewer.py uses live cairo to draw a red house
   at Home location (Timaru). Peak of the roof is at the lat/lon of
   Home location.
