Fix broken help indention.

Calling strip first will make the first line have an indentation of
zero, which will cause dedent to do nothing at all.
Prepare for 0.3.1 release
Run tests on Python 3.4
Merge branch 'docstring_indention' of https://github.com/untitaker/argvard into docstring-indentation
Mention docstring dedent issue in changelog
Install Python 3.4 on travis