Merge pull request #667 from txiki31/3.2-integration

(closes #3635) Change maintenance page
Beautify logmsg (refs #3609)
Add warning message in dialog(closes #3609)

Add warning message in custom function or dialog
force app AUTHENT if not defined (refs #3463)
Merge pull request #668 from Eric-Brison/3.2-I3636

force app AUTHENT if not defined (refs #3463)
Code enhancement (refs #3609)

Suppress notice from phpStorm
Style enhancement (refs #3609)

Change some dialog option
Add SYSTEM tag to core applications (closes #3624)
correct defattr for modattr (refs #3620)
Merge pull request #671 from Eric-Brison/3.2-I3636

correct defattr for modattr (refs #3620)
Merge pull request #669 from cbonnissent/3.2_3609

Open warning message in dialog or custom function
Merge pull request #670 from thingthing/3.2-A3624

Add SYSTEM tag to core applications (closes #3624)
Delete htmlarea files (closes #3518)
Change comment of canEdit (closes #3517)
Merge pull request #672 from txiki31/3.2-integration

3.2 integration
Merge pull request #673 from thingthing/3.2-I3518

Delete htmlarea files (closes #3518)
Merge pull request #674 from thingthing/3.2-I3517

Change comment of canEdit (closes #3517)
Add "/" to delimiter for preg-quote (closes #3631)
Merge pull request #676 from thingthing/3.2-A3361

Add "/" to delimiter for preg-quote (closes #3631)
Correct delimiter (closes #3631)