Minor pep8 changes. Most salient is that membership test should be 'x not in y' whereas 'not x in y' was being used.
Adding more verbose message for understanding, descriptor usage for learning, and Fixed all errors/warning for PEP8
Fixed python3 errors
Small change in output : Methods of factory should print 'We have...' since they are the once only producing the object',  object specific methods can start from 'It is ...'
Added table with links and descriptions.

Fixes #53.
Merge branch 'dsoprea-master'
Merge branch 'arovit-master'
added the state variable to borg and improved the README
Merge branch 'luoxing91-master'
append_output.sh for 3-tier and null
removing null, it is not considered pythonic
better prototype example
better decorator example
added the output of decorator