add aspect fix mode support - closes #177 - refs https://github.com/mapnik/mapnik/commit/422f3bd8b07d27f7a81f3ac1f0dea8d3a34763c8
new mapnik SDKs
Merge pull request #299 from mapnik/aspect-fix

Aspect fix
finish exposing aspect_fix_mode
v1.4.13
[publish binary]
Updated S3 link to new Windows mapnik sdk
[publish binary]
stop building against Mapnik 3.x as we'll target directly in next release [skip ci]
fix #302
Add to changelog
pass variables from js to c++ for vtile.render
make binding.gyp more cross-platform by default
strip newlines in svg test
allow a few windows tests higher tolerance
use new mapnik-sdk
try new win sdk
tweak windows unpacking directories
make sdk build on windows easier to run partially
appveyor: back to requiring tests pass