Add some alias and some errors' test.
Add Forklift::Client::Catalog.
Change catalog and gd to OO, re-gen vcr cassettes.
Almost OO!
Add magic encoding.
Update README.
Raise ArgumentError when no apikey or secret.
Merge branch 'master' into dev

Conflicts:
	lib/forklift/client.rb
	lib/forklift/utils.rb