add fun-certificates app containing the module generator.py and the command generate_fun_certificates.py
remove useless loop in COURSE_LISTINGS
#648 PEP8 corrections
#648 add reportlab requirement, used in the generation of certificates.
#599 Add option set-grade to add external grade
#642: add all settings
remove ident for debug purpose
remove if
#648 test existance of 'grade' option before converting it to float
#648 also generate the certificate when we set the external grade
#669 add command to enroll all students to a mooc
#699 debug queryset
#665 add admin.py
#669 correct typo in usage
#669 rename script from register_all_students to enroll_all_students
#648 do not filter students that haven't a profile
Merge pull request #6 from openfun/#669-register_all_users_to_a_mooc

#669 generic script to enroll all students to a mooc
Merge pull request #7 from openfun/#648-certificates-generation

#648 FUN certificates generation
Merge pull request #5 from openfun/#665-add-GenereratedCertificate-model-to-admin

#665 add FUN GeneratedCertificate model to admin
#675 bug fix : 404 and 500 pages were not rendered