Provisioning fixes.

0. Support for multiple OS targets.
1. Dependency fixes for gcc-arm, curl, etc.

r=@fnoble,@imh,@cbeighley
Fix RaspberryPi OSTYPE = linux-gnueabihf match in setup.sh.
Update README for Vagrant use.
Merge pull request #200 from mookerji/182-vagrant-fix

Provisioning fixes (including Debian).