test: Extend testPrepare, and add testErrors
test: Extend testPrepare, and add testErrors

Properties:

 * prepare conn "BEGIN; ..." does the BEGIN, and only the BEGIN.

 * Violating unique or not null constraint throws ErrorConstraint.

 * If parameter index for bindSQLData is out of range, it throws ErrorRange.

 * If column index for 'column' is out of range, it returns SQLNull.

IreneKnapp/direct-sqlite,IreneKnapp/direct-sqlite