Move open_fixtures() method to CleoTestCase class.
Updated get_display() method of testers to always return an utf-8 string.
Added missing fixtures_path attribute to CleoTestCase class.
Added tests for Command class.
Adds Travis support.
Adds HelpCommand tests.
Changes IS_ARRAY constants to IS_LIST constants.

Also changes the is_array() methods to is_lists().
Adds tests for ArgvInput class.
Adds tests for output classes.
Adds tests for InputDefinition class.
Adds missing fixture file.
Adds tests for formatters classes.
Fixes a test for OutputFormatter class.
Adds tests for ListInput class.
Removes orderredict dependency.
Adds tests for formatter helper.
Merge pull request #6 from SDisPater/fully-tested-code

Fully tested code