Store user data under user's home directory

This should relieve any permissions issues with devkit.
Use portable recursive copy tool
Merge pull request #23 from gameclosure/feature-user-data

Feature user data
Roll our own recursive copy that maintains perms
fix (devkit cli): add support for nodejs vs node

On some linux systems (debian, others?), the node package name is
already taken, and the node binary we are expecting is named nodejs.
This changes the devkit command line script to try nodejs first, then
fall back to node.

Tested on OS X 10.9.5 and Ubuntu 14.04.1.