use nmake for harfbuzz since cmake can't create visual studio 2014
files. Previously this worked because I had visual studio 2012 on
my system but this fails on a system with only 2014.
newest png expects zlib 1.2.8 - lets hope the tiff error does not return
add harfbuzz to master build script
target mapnik 3.x now
Add more build deps
remove hardcoded zlib version