Add a "not yet implemented" error for all back-compat switches so user gets an actionable error message

[stuartpa]

If there are any switches left from the old ODBC sqlcmd that are not yet implemented in the new go-sqlcmd, please put in a stub implementation for go-sqlcmd now, which gives an actionable error message.

We are seeing some cases where go-sqlcmd is being drop in replaced with the old ODBC sqlcmd and the swithch synatac isn't identical (-N right now is an example, -N in go-sqlcmd needs a parameters, e.g. -N true, whereas in ODBC sqlcmd, it is just "-N")