Merge pull request #17 from hguemar/master

Add troubleshooting subsection to development documentation
List dependency to dateutil
Add dateutil as a requirement to build the doc
The library is called python-dateutil not dateutil
Let's try to import only the __version__ from the fedocal modul
The module is called python-datetutil and is already listed in the requirements
Let's not retrieve __version__ from the fedocal module for the moment anymore