Add native workshop support

To add on the instruction page:
To get the workshop auth code, go to http://steamcommunity.com/dev/apikey and generate a code.
To get the workshop collection id, take the URL, for example http://steamcommunity.com/sharedfiles/filedetails/?id=123456789, and use the trailing numbers for the id value.
Added link to the wiki page
Merge pull request #103 from Scarsz/patch-1

Add native workshop support