Remove outdated information from README.rdoc
Make more explicit assertions in CLITest
Move test help screen data to a fixture
Move test/data to test/fixtures.

Moved test/data to test/fixtures and renamed the method #load_file
to #load_fixture.
Remove unnecessary comments.
Remove unused variable.
Fix warning by naming test properly
Use better assertions
Replace ' with " and remove some parenthesis
Fix bug when searching for undefined words

When searching for a word that is not on urban dictionary an exception
would be raised and printed on the screen.
Replace more test constants with fixtures