windows tests failing with node v4

[mapsam]

The appveyor tests are failing on node v4 due to some gdal 403 errors, here's the binary that needs to be installed:

https://mapbox-node-binary.s3.amazonaws.com/gdal/v0.9.4/v140/node-v46-win32-x64.tar.gz

@springmeyer hard to tell if this is actually an AccessDenied or if the binaries just don't exist in the first place.

[springmeyer]

Took a look at this. The binaries do not exist. This is expected since currently node-gdal does not build node v4 windows binaries against the C++11 version of node (which this is, since we see the v140 which distinguishes the custom Visual Studio runtime built by https://github.com/mapbox/node-cpp11).

So, the unfortunate take home here is that mapnik-omnivore is only currently working with node v0.10.x on windows. So the change to the appveyor.yml here will need to be reverted until @springmeyer and @BergWerkGIS come up with a plan to finish node v4 support for windows (or find a way to dodge that work).

[mapsam]

Thanks for investigating @springmeyer! I just changed appveyor back to 0.10.x. Sounds like a pretty big lift for the time being - closing for now.

[mapsam]

37b6b89