Allow execution with missing Vendorfile.
Add warning when missing a Vendorfile.
Spec cleanup - remove vendorfile fixtures.
Load Vendorfile only for the tasks that need it.
Improve error messages on failed Vendorfile load.
Add feature for empty Vendorfile support.
Add feature for missing a Vendorfile.
Add feature for missing Vendorfile error message.
Adjust test for weird thor/rake "compatibility".
Merge branch 'develop' into feature/vendorfile-loading

Tough merge, there were some conflicts in cucumber tests, but seems
all right now.
Adjust cucumber test for varying line length…
Merge pull request #25 from 3ofcoins/feature/vendorfile-loading

Allow missing Vendorfile