TODO list
=========
- add import time to metadata
- manage cross-references
- find (authors) duplicates
+ remove command
- stats command
+- add query support to list command (cf beets)
- FIX open on ubuntu
+- edit bibtex on add
+- option to add tag on add
- paths in metadata must be relative
- include package data in setup.py (see setup.py for more info)
- in the script papers, why do we use a dictionary and not a list? it may be confusing, the key is not the subparser name. The subparser name is defined in the cmd files
- command to output a bibfile from several citekey or even a research results