Properly print query SQL in debug mode
Refactor ODBC::GetColumnValue

Split into GetCColumnType, GetColumnData, and ConvertColumnValue to
allow ODBC::GetColumnValue (async) to do the data-getting on the worker
thread and the conversion in the callback on the V8 thread.
Returns a Buffer if the data type of the column is SQL_BINARY or
SQL_VARBINARY.
Converts the 'bit' data type into true/false using the SQL_C_BIT data
type rather than SQL_C_TCHAR.