Stable version 0.3.7

This is purely a bugfix bump that compiles on GHC 7.10
and uses a regex lib that doesn't crash on OS X.

ShellCheck.cabal

 Name:             ShellCheck
-Version:          0.3.6
+Version:          0.3.7
 Synopsis:         Shell script analysis tool
 License:          AGPL-3
 License-file:     LICENSE