modified the behavior of filter_english_with_letters to mimic the behavior of mozillas version
improved filter_without_english_letters code for readability and performance
fixed a minor problem with the operators
updated to using regex to filter international words. added docstring and comments. note - not compatible with P3
made changes for compat with py3
improved docstring
Merge pull request #44 from rsnair2/master

Modified filter_english_with_letters to mimic the behavior form Mozilla's version.