Use https://rubygems.org as source in Gemfile

Per latest recommendations for downloading gems:
http://bundler.io/v1.3/gemfile.html
Remove Gemfile.lock from git

Per recommendation:
http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/
WIP levenshtein recursive implementation
levenshtein implementation with dynamic programming
handle deletion by reversing order of loops
levenshtein spec contexts for arrays and strings

levenshtein spec contexts for arrays and strings

remove extra gems
adds levenshtein wikipedia entry to README
documentation for levenshtein algorithm