Make transaction checking explicit when executing statements inside connection
SQLText fixes

• Stop storing quotes in string literal and quoted identifier nodes
• Stop appending trailing ';' to statement lists; this makes a single statement have no semi-colon (which is better for the current unit tests)
Fix Date,Time and Timestamp escape processing

• Recognizes escapes format correctly
• Outputs to postgres format that is always recognizable
Fix misspelled SQL command for isolation level
Fix parsing of command tag in protocol

• Parse CREATE and DROP command tags
Migrate connection unit tests from original project