A bunch of changes for get a good debian package

I added some files and infrastructure for make reality a debian package. It would be great if you can get a version with a changelog file. I think that would be the initial release (0.1 or whatever) and the changelog would be "initial release with this features".

Also, I added a file .travis.xml for continuous integration but is necessary set up the service. You can do it in https://travis-ci.org/.

I removed the docstring test cases because is not possible run them in Python3 and Python2. I used unittest for rewrite the test cases and I tried add more cases as well.

I added some new methods for get "a better API" like transaction, begin and save.