Changed background color from style to css class

Added classes to tdd-state-tracker.css.
changed "color" to "className" in TDDStates.
Refactored state element changes to changeStateElement function.
Added support for timestamper.
Added EOL to EOF.
Added tdd-state-tracker.css stylesheet to tst/index.html
Changed tests to check currentState instead of initState() or update()
return value.
Refactored checks to separate checkTDDState function.
Since checkTDDState checks both tracker.currentState and testElement
settings, removed separate testElement tests.