androidmanifestfingerprint returns the manifest files for each apk file.
androidmanifestfingerprintfactory return an androidmanifestfingerprint.
ratcliffmetric uses the difflib library in python. However, the following resources are important to understand how this metric works.

http://xlinux.nist.gov/dads/HTML/ratcliffObershelp.html
http://docs.python.org/2/library/difflib.html#difflib.SequenceMatcher
http://www.drdobbs.com/database/pattern-matching-the-gestalt-approach/184407970?pgno=5
added files for git to ignore!!c
Added code to create a tree with the ratcliffmetric..
Code to create a graph or tree based on the number of roots. If more than one root than create a DAG else create a tree.