Add new signal/slot connection syntax to KisSignalAutoConnection
- Use template to accommodate the new syntax of signal/slot connection.
- Instead of the four parameters passed to QObject::connect(), we
store the QMetaObject::Connection returned by connect(), and use that
to disconnect() it afterwards.
- There is a unit test to test the auto-(dis)connection, just to
make sure it works with both syntaxes.
- There is no need to change any existing code involving
KisSignalAutoConnectionsStore, unless you want to replace the old
syntax with the new one.