node v0.10.x support

This added support for node v0.10.x. Tested with node v0.8.2 and v0.10.7 on OS X.

Does not work with node v0.10.8/9 due to a node bug as per https://github.com/developmentseed/node-blend/issues/31#issuecomment-18716078

Ready to merge once we test on Ubuntu.