make the simplify test function general purpose so others can add other test cases for other simplification algorithms
make the simplify test function general purpose so others can add other test cases for other simplification algorithms

davenquinn/python-mapnik,cjmayo/mapnik,mapycz/mapnik,rouault/mapnik,garnertb/python-mapnik,mapycz/mapnik,mapnik/mapnik,Airphrame/mapnik,jwomeara/mapnik,jwomeara/mapnik,cjmayo/mapnik,jwomeara/mapnik,davenquinn/python-mapnik,mapnik/mapnik,pramsey/mapnik,whuaegeanse/mapnik,zerebubuth/mapnik,Airphrame/mapnik,CartoDB/mapnik,sebastic/python-mapnik,pramsey/mapnik,yohanboniface/python-mapnik,lightmare/mapnik,lightmare/mapnik,davenquinn/python-mapnik,zerebubuth/mapnik,mapycz/python-mapnik,pramsey/mapnik,tomhughes/mapnik,mbrukman/mapnik,jwomeara/mapnik,whuaegeanse/mapnik,naturalatlas/mapnik,zerebubuth/mapnik,mapnik/python-mapnik,manz/python-mapnik,naturalatlas/mapnik,rouault/mapnik,Uli1/mapnik,yohanboniface/python-mapnik,manz/python-mapnik,mapnik/mapnik,whuaegeanse/mapnik,pramsey/mapnik,sebastic/python-mapnik,cjmayo/mapnik,manz/python-mapnik,stefanklug/mapnik,mbrukman/mapnik,mapnik/python-mapnik,pnorman/mapnik,stefanklug/mapnik,mapnik/mapnik,rouault/mapnik,cjmayo/mapnik,mapnik/python-mapnik,pnorman/mapnik,sebastic/python-mapnik,tomhughes/python-mapnik,mbrukman/mapnik,CartoDB/mapnik,yohanboniface/python-mapnik,mapycz/python-mapnik,pnorman/mapnik,naturalatlas/mapnik,tomhughes/python-mapnik,mbrukman/mapnik,pnorman/mapnik,Airphrame/mapnik,tomhughes/mapnik,Uli1/mapnik,Uli1/mapnik,stefanklug/mapnik,tomhughes/mapnik,rouault/mapnik,garnertb/python-mapnik,Uli1/mapnik,naturalatlas/mapnik,tomhughes/mapnik,whuaegeanse/mapnik,lightmare/mapnik,stefanklug/mapnik,garnertb/python-mapnik,tomhughes/python-mapnik,CartoDB/mapnik,mapycz/mapnik,Airphrame/mapnik,lightmare/mapnik