Update yunohost_app.py

Correction
Merge pull request #60 from M5oul/patch-1

Update yunohost_app.py
Correct yunohost-config-dspam mess
Allow no arguments in manifest
Update yunohost_firewall.py
Fix empty password breach
Merge pull request #62 from jeromelebleu/dev

Fix empty password breach
Update yunohost_tools.py
Merge remote-tracking branch 'upstream/dev' into test