bugfix for similar_text.js

Fixing similar_text.js based on findings on http://stackoverflow.com/questions/14136349/how-does-similar-text-work

Basically, in some cases the algorithm is not implemented correctly. It shouldn't produce the same result when swapping the input words but it seems to do so.
Merge pull request #104 from eis/patch-1

bugfix for similar_text.js