This patch modifies AppendEdgecodeSlot in ImplAAFSourceMob, to work like AppendTimecodeSlot.
AppendTimecodeSlot is also refactored with smart pointers.
CAAFSourceMobTest is then amended to test the behavior of the time code and edge code slots.
Namely, new slots are added, values in the added slots are then modified, and lastly the slots are red back and the values checked.
The patch of CAAFSequenceTest is not related to SourceMob.
The sequence unfortunately allows modification before it is initialized.
Appending components to the sequence succeeds even when the sequence has not been initialized.
The patch creates a new characterization test which confirms the behavior, documents it, and recommends a fix.