Add output flush callback

Jan Breuer

2012-12-26 100e86891d03181d5a77639b903e799e97ffb187

 libscpi/inc/scpi/types.h

@@ -102,6 +102,7 @@
    struct _scpi_interface_t {
        scpi_error_callback_t error;
        scpi_write_t write;
        scpi_command_callback_t flush;
        scpi_command_callback_t reset;
        scpi_command_callback_t test;
        scpi_command_callback_t srq;