adding python3 support
fixed ISO C90 compatabliity so will work on windows, highlighted by 3.4 build
ctypes searching fixes required to run on the travis ci python3 env, travis install copies cHeatmap.cpython-*.so instead of cHeatmap.so
added better coverage for tests as well as python version test for >=2.6
fixed tests for older versions of unittest, uses function assignment as no __version__ is available
cleaner to include rather than omit in coveragerc
added back version code
cleaned up srcepsg and dstepsg docco
added image comaparison tests and split out the repeated saveKML functionality
removed forced exit if not python 2.6+, added trove classifiers