(to construct custom 'Output' derive from feature_style_processor (CRTP) e.g
class MyOutput : public feature_style_processor<MyOutput>
and implement:
process(***_symbolizer const&, Feature const&)
methods
At the moment only AGG renderer is implemented
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
