Fixes failures when RACK_ENV is set

The with_environment spec helper only took into account RAILS_ENV, this
should fix it by setting/resetting RACK_ENV at the same time
Merge pull request #10 from HouseTrip/forgot-rack-env

Fixes failures when RACK_ENV is set
Fixes require for Ruby 1.9
Merge pull request #9 from HouseTrip/ruby19

Fixes require for Ruby 1.9
Adds Travis badge
Replaces  by $:
Removes unecessary comment and load path modification
Makes wait_schedule return the exit status of the process
Merge pull request #12 from HouseTrip/travis

Adds Travis badge
Merge pull request #13 from HouseTrip/ruby19

Ruby19
Typo
Merge master into fixes-test-suite (using imerge)