Added signed int output for ADC Devices
Changed uint32_t to int32_t, allowing for signed output. Needed for MCP3428 differential ADC. Adjusted Linear calibration to allow for this along with reference max and reference min.
Changed uint32_t to int32_t, allowing for signed output. Needed for MCP3428 differential ADC. Adjusted Linear calibration to allow for this along with reference max and reference min.