Allow the word size to be configured and minor usability updates

- Added word_size configuration to allow words that smaller than 3 characters to be filtered.  Also gives the ability to go up in size. Prior to this modification it was hard coded at 3.  Default is 3 so existing implementations are not broken.
- Added new unit tests for word_size
- Modified unit tests to allow them to be run in RubyMine as well as command line as it is today.
- Updated gemspec so the version is pulled from the version file.  This centralizes the version to one location.