allow the list of extensions to be customized.  also, use glob to build
the file list so we don't watch EVERY file in our project which quickly
consumes resources.  this way we only watch those files that match the
extensions we specify.
Merge branch 'master' into choose-extensions

* master:
  0.4.0
update in-app help
Merge pull request #6 from seancoyne/choose-extensions

Choose extensions
0.5.0