0.31.3

• Fix return value of ExecuteScalar to be the first column from the first row of the first result set.
• Fix return value of ExecuteNonQuery to correctly return -1 for SELECT statements.
• Fix bug where NextResult returns true for a trailing comment in a SQL statement.
• Breaking Throw InvalidOperationException if MySqlCommand.CommandText is set while the command is active.
• Breaking Throw InvalidOperationException (instead of MySqlException) if a MySqlCommand is executed while there is an open reader.
• Breaking Throw InvalidOperationException from MySqlCommand.Prepare when preconditions aren't met.