FakeVim delete lines by pattern not functional

Deleting all lines containing a pattern seems not to be implemented:

:g/MyPattern/d

after hitting this in Vi Mode, it says: ":g is not an editor command"

This should be implemented, it belongs to the most imporant features of Vi like stuff.

It is basic functionality.

Tested only on specified QtCreator version, but i guess it applies to all versions.