Make clarification in the documentation of Animation#advance
Add spec for GosuGUI::Animation
Add spec for Utils class methods
Add spec for Utils::Clock
Rename the offset file in Utils to helpers

Because the file no longer holds only offset methods.
Remove tests im not happy with

Some of them depend on the machine they are being run on.
Fix Direction#== with angle to work with angles > 359 and < 0
Use approximate equality when comparing Direction with symbol
Add to the description of Direction#to_s
Add spec for Utils::Direction
Rename the old offset spec to match which its new name
Leave spec only files for the classes that will be tested
Fix typo in module name
Add play and quit aliases to the Game show and close methods