win_updates: Add module to install windows updates

Supports specifying which category to install all updates from.
**NEEDS:** `choco install PSWindowsUpdate` beforehand - does not attempt to install it (or detect it's missing, yet). Can be done via #37.

PSWindowsUpdate: http://gallery.technet.microsoft.com/scriptcenter/2d191bcd-3308-4edd-9de2-88dff796b0bc#content