Added a howNotArabic() function.
Update arabicString.js
Added howNotArabic() & removeTashkel()

Added two functions, 

1- howNotArabic() will return the opposite of howArabic(). e.g. 'فوو bar'.howNotArabic() will return 0.5

2- removeTashkel() will strip the Arabic diacritics from the 'String' and return it
included doc's for howNotArabic() & removeTashkel()
Formatting
Update arabicString.js
Added removeArabic() & removeNonArabic()
Merge pull request #2 from YazeedAlsaif/master

Added howNotArabic(), removeTashekl(), removeArabic() & removeNonArabic() to arabicString.js