Added libqt5sql5, to Debian depends

This fixes an issue where the client will not run, with message "error while loading shared libraries: libQtSql.so.5: cannot open shared object file: No such file or directory".
Merge branch 'pr577'
Handle received group actions
Jump to Add Friend form when quitting groupchat

Fixes part of #579
Fix minimumSize being too small

Fixes part of #579, graphical glitches with the splitter
Italian translation: update
Merge branch 'pr580'