Supporting Arduino chips with Multiple SPI busses

[skipper762]

Allowing the passing of a pointer to an SPI bus of the users choosing, so that chips with multiple SPI busses (Teensy, Zero ..) can use the library on the other busses I.E (SPI1, SPI2, mySPI)

[skipper762]

I have forked your repo and updated the library to fix this issue. There is now an extra constructor that has the following form:
MCP3208(uin8_t, SPIClass)

Can be used like:
MCP3208(10,SPI1)

Can be found here:
https://github.com/skipper762/MCP3208