Replaced ruby bin call with /usr/bin/env ruby

This way the environment can decide which interpreter got to be used.
It's absolutly usefull if we try out other ruby versions or to use
another path for the ruby binary.
Merge pull request #77 from tboerger/feature/bin-replace

Replaced ruby bin call with /usr/bin/env ruby
Merge pull request #82 from dirkmueller/release/stoney/master

Release/stoney/master
Enable scenario tests