Bug fix and some improvements

I fixed a bug in Synonyms where it didn't calculate the top three
scoring synonyms properly. I have also added what I've done so far which
is:
-Changed to HashMap<String, double> for better precision
-Added som scoring, now instead of raw term frequency, each term score
based on its wordlength and the tf-idf score from the document is was
found. Thus favorising terms that are longer, more frequent and from
more relevant documents.
Merge branch 'master' of https://github.com/Berjiz/ir_synonyms

Conflicts:
	HashedIndex.java