Merge pull request #259 from bbfsdev/fix_content_data_format

Fix content data format
updated version to 1.6.1
removed dependency on rake (testted both normal and backgroung execution)
Merge pull request #263 from bbfsdev/issue260_diff_performance

Issue260 diff performance
Update README

Project requirement updated from Ruby1.9.3 to Ruby2.1.1
Merge branch 'master' of ssh://github.com/bbfsdev/bbfs into add_google_hashes
update test to 350K.