Windows Support + Updated Ruby SDK

This release reintroduces Windows support. It also contains multiple fixes for issues #150, #153, #149, #147.

Notable Changes:

• Windows Support! Thank you, @matt-richardson!
• Updated dummy.box in the root of the repo
• Update the Azure SDK libs to 0.8.0
• Update to use Premium storage for faster deployments
• Don't wait on destruction of the resource group, but just issue the delete call
• Update the VM to Standard_DS2_v2 by default
• Don't default to NFS, but rather fall back to rsync by default
• Default admin username and password, which was causing failures when spinning up a default linux box
• Remove boot diagnostics from the VM to simplify the storage dependency and speed up provisioning