Add options for windows installation

A different installation process is provided to beginners to give them a
simpler setup. If you're new to programming, navigating a VM is going to
be an overwhelming experience.

For those more experienced it will not be a problem, and the VM will
provide a better development experience.
Revert "add osx vagrant installation"

This reverts commit 7d10fc7a37789759cd9e1a4dd9e18f812f679bf7.

Conflicts:
	sites/en/installfest/osx_vagrant.step

The volunteer group decided that it was preferable to use the OSX RVM
install over a VM.
Update download instructions for OSX

Based on the removal of the VM as an install option.
Merge pull request #3 from railsbridge-montreal/feedback-install-updates

Feedback install updates. Closes #1