[PEAK] _startDBTxn

[Erik Rose]

I thought I'd finished my ADOConnection class (which wraps an MS ADO 
data source to present a PEAK ISQLConnection), but then I noticed the 
_startDBTxn method, which SQLConnection's setTxnState calls. It seems 
like I ought to implement it to call self.connection.begin(), but, 
OTOH, PGSQLConnection doesn't define _startDBTxn at all. Is _startDBTxn 
unnecessary, or is PGSQLConnection broken?

Thanks,
Erik