consolidate shebang logic
Simplify shebang detection
Add tests for shebangs
Don't bother creating an instance
Deprecate find_by_shebang

This class doesn’t need to know about shebangs.
docs
require shebang when building samples
Treat lines as enumerator and not array
Fix shebang without path
Remove Linguist.interpreter_from_shebang
Merge remote-tracking branch 'origin/master' into move-shebang

* origin/master:
  Tweak docs
Merge pull request #1787 from github/move-shebang

Move shebang (updated)