Merge pull request #973 from ngodfraind/master

Max storage size per workspace.
Merge pull request #974 from ngodfraind/master

Default directory "my documents" in personnal workspace.
Merge pull request #975 from ngodfraind/master

Destination can be chosen during the upload.
add creation button on group list
Merge pull request #976 from LaurentGruber/add-group-btn

add creation button on group list
Merge pull request #977 from ngodfraind/master

Personal workspace configuration (beginning)
Merge pull request #978 from ngodfraind/master

Rich text can be handled by the export/import workspace function.
Merge pull request #979 from ngodfraind/master

Rich text can handle unexisting files.