Fix Microchip harmony command backspace handling

sys_command.c

case SYS_CMD_STATE_WAIT_FOR_READ_DONE:
{
    if((readBuff[0] == '\r') || (readBuff[0] == '\n'))
    {
        pCmdIO->cmdState = SYS_CMD_STATE_SETUP_READ;

        // new command assembled
        if(pCmdIO->cmdPnt ==  pCmdIO->cmdBuff)
        {   // just an extra \n or \r
            (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, LINE_TERM _promptStr);
            return true;
        }
        (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, LINE_TERM);
        *pCmdIO->cmdPnt = 0;
        pCmdIO->cmdPnt = pCmdIO->cmdEnd = pCmdIO->cmdBuff;

        if(!ParseCmdBuffer(pCmdIO))
        {
            //Command not processed, show prompt
            (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, _promptStr);
        }
        else
        {
            //Command being processed, temporarily disable prompt until command completes
            pCmdIO->cmdState = SYS_CMD_STATE_DISABLE;
        }

        return true;
    }
    else if(readBuff[0] == '\b' || readBuff[0] == 127) // VG: check DEL character as well
    {
        pCmdIO->cmdState = SYS_CMD_STATE_SETUP_READ;

        if(pCmdIO->cmdPnt > pCmdIO->cmdBuff)
        {
            (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, "\b \b");
            pCmdIO->cmdPnt--; pCmdIO->cmdEnd--;
        }
    }
    else if(readBuff[0] == 0x1b)
    {

        _cmdAppData.seqBuff[0] = readBuff[1];
        _cmdAppData.seqBuff[1] = readBuff[2];

        // This is an escape sequence, start reading which cursor character
        ProcessEscSequence(pCmdIO);

        readBuff[0] = '\0';
        readBuff[1] = '\0';
        readBuff[2] = '\0';

        pCmdIO->cmdState = SYS_CMD_STATE_SETUP_READ;
    }
    else if(pCmdIO->cmdEnd-pCmdIO->cmdBuff<SYS_CMD_MAX_LENGTH)
    {
        pCmdIO->cmdState = SYS_CMD_STATE_SETUP_READ;

        if (readBuff[0]!='\0')
        {
            (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, readBuff);
            *pCmdIO->cmdPnt++ = readBuff[0];
        }

        if(pCmdIO->cmdPnt > pCmdIO->cmdEnd)
        {
            pCmdIO->cmdEnd = pCmdIO->cmdPnt;
        }
    }
    else
    {
        pCmdIO->cmdState = SYS_CMD_STATE_SETUP_READ;

        (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, " *** Command Processor buffer exceeded. Retry. ***" LINE_TERM);
        pCmdIO->cmdPnt = pCmdIO->cmdEnd = pCmdIO->cmdBuff;
        (*pCmdIO->pCmdApi->msg)(pCmdIO->cmdIoParam, _promptStr);
    }
}
break;

if(readBuff[0] == '\b' || readBuff[0] == 127)