better development deps
Fix RACK_ENV exception in development mode.

Getting RACK_ENV out of OS env directly means
development-as-default behaviour does not occur, at least on
Rails (but presumably on other Rack stacks, too).
Allow use of ERB in riak.yml. Handy for 12factorizing your app.
RACK_ENV considered harmful.  Use Rails.env if it exists.
switch to gntp for growl notifications on mac