Set the verbosity level through parameter.
Adjust environment spec.
Introduce an IO proxy object to handle output.
Adjust tests for the new IO.
Merge branch 'develop' into feature/verbosity-levels

Conflicts:
	lib/vendorificator/vendor.rb
Merge pull request #21 from 3ofcoins/feature/verbosity-levels

Feature: verbosity levels.
Merge branch 'develop' into feature/handle-missing-notes

Conflicts:
	lib/vendorificator/cli.rb
	spec/vendorificator/environment_spec.rb