(FIXME : label_spacing is still, too slow!!)
2. Re-use some agg objects.
3. placement_finder cleanups!
4. Added support for 'building_symbolizer' - extruded polygons
Map and Layer objects both have a new parameter 'srs', initialized to "+proj=latlong +datum=WGS84" by default.
Basic usage (Python):
p = Projection("+proj=merc +datum=WGS84")
point = p.forward(Coord(-2,51))
...
2.reflected arithmetic operators for Envelope/Coord into Python
3.altered return policies for python objects
4.modified build system to require proj4 lib and headers
2. use boost::thread for mutex/lock
3 use boost::noncopyable
4 build agg as a shared lib for now
5. corrected panning code in map.cpp
6. improved coord_transform
