tox: - added dependency on unittest2 for py26
Merge pull request #45 from AvdN/tox

tox: - added dependency on unittest2 for py26
travis-unittest2: added unittest2, use mirrors

--use-mirrors is recommended http://about.travis-ci.org/docs/user/languages/python/#Pre-installed-packages

- added 2.6 and test in yaml
Merge remote-tracking branch 'origin/master' into test_2_6
Merge github.com:kislyuk/argcomplete into test_2_6
test_2_6: - added test for FilesCompleter
- made completers:_wrapcall() python 2.6 compatible
- test.py changes for python 2.6

changed _wrapcall testing for 2.7 to try-except

changes per kislyuk