Update cssassist.js


removed clearing of undefined since it isn't used.
moved version outside of prototype function to make it available as CSSAssist.version
refactored init method (smaller, faster, happier)
removed unnecessary brackets here and there
made hasClass regex case insensitive (performance gain)
factored out regex for whitespace/lines
short-circuit for classlist not defined in hasclass (smaller code)
improved performance of class lookup in hasClass
add array length caching to for loops
factored out iteration (experimental)
improved useCapture defaulting in listener methods
some parameter renaming