Babel is now required for aresource support

Signed-off-by: Michal Čihař <michal@cihar.com>
Document optional deps installation

Signed-off-by: Michal Čihař <michal@cihar.com>
Better variable name

Signed-off-by: Michal Čihař <michal@cihar.com>
Import errors for not supported file formats are now shown in admin page

This prevents these errors will go without noticing.

Signed-off-by: Michal Čihař <michal@cihar.com>
Remove not needed pass

Signed-off-by: Michal Čihař <michal@cihar.com>