Remove unused boilerplate assets.
Spec the behaviour of the rescue in SisowStatusController#update
Merge pull request #7 from berkes/asset-cleanup

Remove unused boilerplate assets.
Merge pull request #8 from berkes/catch-error

Spec the behaviour of the rescue in SisowStatusController#update
Upgrade to 2.2.0

* Assets in spree moved, therefore the install_generator needs to point to other
  assets locations
* I've decided to move the assets in spree_billing_sisow to match the
  new locations in spree.
* Update the references to 2.2.0 in both the Gemfile for
  spree_auth_device and in the gemspec.
* running the dummy installer or the specs failed because spree_core
  does not have Deface nor Spree::CheckoutsController defined. So we
  really need to depend on spree_frontend at the least. We do also depend
  on spree_backend because we insert some links and pages there, yet this
  is either included because of a dependency or not an actual problem.
Mark the new version in the Versionfile
Bump version of this gem.
Make sure sisow is loaded. Checkout and admin wil otherwise flunk.