CatCounterDigit class related code changes
Minor changes in catCounterDigit class interface
Implemented some validity check for parseFloat function result (catCounter.catParseFloat static method)
Trivial test environment tweak
catCounter._parseDigits method minor tweak
Minor methods changes
catCounter DOM building routine changed, _buildDOM and _$buildDOM methods removed
catCounterDigit methods trivial draft written
Minor jsDoc fixes