Added UART handler

[alustig3]

This adds information on how to use the UART_handler class, addresses #33

This may need to be changed pending on the outcome of pyControl/code#166

[ThomasAkam]

Thanks Andy, could you add a note to the docs indicating that the UART handler only works with micropython version >=1.26

[ThomasAkam]

Thanks Andy

[ThomasAkam]

@alustig3 as the UART handler is included in the latest release I guess it should also be in the main branch of the docs rather than the dev branch?

[alustig3]

@ThomasAkam these docs match the latest changes from pyControl/code#166 that are on the code(dev) branch, not the current code(master) branch.

should we merge the code(dev) and code(master) and make a minor 2.1.1 release? and then merge these docs(dev) and docs(master)?

[ThomasAkam]

Sounds like a good plan. Would you be able to do this?

[alustig3]

sure, will do