Count number of decays that have additional pi0
Add check zero-division when all decays are found
Rename hep_translator() to HepTranslator(object)
Add cleanup if class is used with with

Added a __enter__ and __exit__ function. The latter one deletes the
created files and is called when the object is called with the
'with'-statement.
http://stackoverflow.com/questions/865115/how-do-i-correctly-clean-up-a-python-object
Make import non-relative
add todo functionality to sphinx documentation
Extend Comments and minor fixes
Add more parameters and remove trailing ','
Handle seen as br 0 and dominant as br 1
Add subdecay handling to extract_decay_from_lines

Implement a first version of the subdecay handling, but there is still a
lot todo. Especially:
- more than one subdecay
- br is only "seen", etc
- sub decay mother is named differently than the decay name
File handling works now as intended
some minor style changes
Add anti-particle dict and function
Change import syntax
Change import style for tests
change the sphinx theme back to default
renaming minor variables to all lower
Extract function for finding decay in the ref_file
Add test for creating directories
Add create_dir function and fix test