backoffice application
remove bower and add Ink framework to static files
ssue959-add-test-certificate-generation
issue959 repair bad commit on template course.html
issue959 add  TEST_ to certificate filename
#982: restrict backoffice to group fun_backoffice's users
#959 Use string interpolation to build file name
issue959 move make_teachers_list function to form.py
issue959 remove bad decorator in function generate_certificate
#959 display Django framework messages
issue959 introduce django messages instead of raising 404
Merge pull request #27 from openfun/jpaille/issue959-add-test-certificate-generation

#982 Backoffice application
#959 add test certificate generation