Improvements to CSuperComboBox (9)

Improvements to CSuperComboBox (9)

* Eliminate the "AddTemplate" and "AutoAdd" capabilities of
`CSuperComboBox`.  They are never used and it is likely that their
logic is incomplete or incorrect.
* Eliminate the `bAdd` and `idstrAddText`parameters from the
`CSuperComboBox` constructor.  Again, they are never used and have no
meaning without the "AutoAdd" capability.