Fix PlatformIO Compiler Warnings

[crabel99]

When the library is used in Platform IO there are two compiler warnings that are generated.

In file included from .pio/libdeps/sparkfun_samd21_dev_usb/SparkFun MCP9600 Thermocouple Library/src/SparkFun_MCP9600.h:25:0,
                 from .pio/libdeps/sparkfun_samd21_dev_usb/SparkFun MCP9600 Thermocouple Library/src/SparkFun_MCP9600.cpp:21:
/Users/username/.platformio/packages/framework-arduino-samd-sparkfun/cores/arduino/Arduino.h: In member function 'Thermocouple_Resolution MCP9600::getThermocoupleResolution()':
/Users/username/.platformio/packages/framework-arduino-samd-sparkfun/cores/arduino/Arduino.h:116:37: warning: 'res' may be used uninitialized in this function [-Wmaybe-uninitialized]
 #define bitSet(value, bit) ((value) |= (1UL << (bit)))
                                     ^~
.pio/libdeps/sparkfun_samd21_dev_usb/SparkFun MCP9600 Thermocouple Library/src/SparkFun_MCP9600.cpp:193:11: note: 'res' was declared here
   uint8_t res;                                        //define new thermocoupleResolution enum to return
           ^~~
In file included from .pio/libdeps/sparkfun_samd21_dev_usb/SparkFun MCP9600 Thermocouple Library/src/SparkFun_MCP9600.h:25:0,
                 from .pio/libdeps/sparkfun_samd21_dev_usb/SparkFun MCP9600 Thermocouple Library/src/SparkFun_MCP9600.cpp:21:
/Users/username/.platformio/packages/framework-arduino-samd-sparkfun/cores/arduino/Arduino.h: In member function 'Burst_Sample MCP9600::getBurstSamples()':
/Users/username/.platformio/packages/framework-arduino-samd-sparkfun/cores/arduino/Arduino.h:116:37: warning: 'samples' may be used uninitialized in this function [-Wmaybe-uninitialized]
 #define bitSet(value, bit) ((value) |= (1UL << (bit)))
                                     ^~
.pio/libdeps/sparkfun_samd21_dev_usb/SparkFun MCP9600 Thermocouple Library/src/SparkFun_MCP9600.cpp:273:11: note: 'samples' was declared here
   uint8_t samples;
           ^~~~~~~

This PR simply initializes the values with the null value and removes the compiler warnings.

[PaulZC]

Hi @crabel99 ,

Thank you for the contribution - and apologies for the very slow reply!

Merging...

Very best wishes,
Paul