Improvements

Improve OAuth dance, by making the message more explit and better formatted
Improve OAuth failured logging
Improve show builds command. If there are no build definitions say so explicitily
Use default repos on vso today and vso commits commands instead of iterating over all repos
Renamed commands
Add commands to catch unhnadled vso commands and respond with a user hint instead of silently ignoring it
Add vso help command to search in msdn forums related to VS online