This involved many changes, some side effects of the change include:
- remove of all `u"abc"` forms, in favor of
`from __future__ import unicode_literals`. Their usage was
inconsistent anyway, leading to problems when mixing with
unicode content.
- improve the tests, to allow printing for usecase even when
crashing. Should make future test easier. This is done with a
rather hacky `StdIO` class in `p3`, but it works.
- for some reason, the skipped test for Python 2 seems to work
now. While the previous point might seem related, it is not clear
that this is actually the case.
Add a theme section in the configuration file to allow users to
set the colors used by different elements of the ui.
Improve the update mechanism so that incremental changes to the
configuration file can be incorporated.
* only bibtex format is supported
* all tests except test_repo.py and edit test pass
* edit and update commands were not updated
* removed --format argument from export, only bibtex is supported.
