created mailgun_helper_spec.rb and mailgun_spec.rb files
tests for loaded libraries in mailgun_spec.rb
adding context to mailgu_helper_rspec.rb
Done tests for create_mailbox method
Small fixes on require libraries
Merge branch 'develop' of https://github.com/romikoops/howitzer into kurenkov
Completed tests for mailgun_helper.rb
Removed commented code from the file
Refactored folder structure for spec files, improved requires in files
Refactored folder structure - updated
Merge pull request #38 from yuramax/kurenkov

Yuriy Kurenkov