activate the $user@$hostname in the default prompt.
flake8 corrections.
Merge branch 'release/1.0'
Merge tag '1.0' into develop

powerline-shell-1.0
Add user and host from a function; new colors for failed/passed/dirty, and use different colors if being root or not (as a sysadmin as often use `sudo -s` and need my prompt to make it clear).
Add a screenshot and update the README.
README img path fix
Major changes in `README`: new functionnalities, success report on different applications, links updates.
Merge branch 'release/1.1' to resync `develop` and `master` branches.
Merge tag '1.1' into develop

powerline-shell-1.1
Small typo in readme
Merge branch 'release/1.1.1'
Merge tag '1.1.1' into develop

powerline-shell-1.1.1
`add_cwd_segment()`: why oh why `names[:2]`??
lower the number of path components in the CWD display, 5 is really too much for a 13,3' MBPr.
Merge branch 'release/1.1.2'
Python 3.3 compatibility. WARNING: will not work with Python 3.{1,2} because of u''. But at least work with Python 2.7 and 3.3 with the same file without the need to duplicate the work.
Merge branch 'release/2.0'
Merge tag 'powerline-shell-2.0' into develop

2.0
Add Python 2/3 compatibility, and readability.