Fixed "TypeError: unicode argument expected, got 'str'" raised by `install_theme` command.
Merge pull request #229 from mrabbitt/feature/install_theme_unicode_error

Fixed for install_theme error:  "TypeError: unicode argument expected" 
Merge pull request #228 from okin/master

Fixing failing tests under Py3K
New version of sitemap_gen.py - now using 1.5. Altered it a little bit so no errors show up when running the task with Python 3.