replace url_character by url_for
remove other url_character calls, keep those in character pages
move the url_character function to WebCharacter.py
Merge pull request #202 from pascalmolin/remove_url_character

Remove url_character calls
fix wrong expansion for dirichlet L functions
Merge pull request #209 from pascalmolin/fix_dirichlet_L_expansion

fix wrong expansion for dirichlet L functions