Bump the actual version number

Would love Arduino library index to just use git tags :(

Adjust argument name to avoid confusing some compilers

Add an example to README

Version 1.2

-Added capability for Proportional On Measurement
-Changed license from GPLv3 to MIT

moved library code back to root from sub-folder

when github was adding a hash to the library download zip, there was confusion from beginners about needing to rename the unzipped folder before moving into the arduino ide.
this library has been prepped (thijse) for the arduino library manager, which requires the library to be in the root directory.  Having the library in the manager also removes the "beginner user hash" concern.