This change removes file-relative include paths and adds the project root as a global include path.
* Project root added to CMakeLists.txt so that all targets can find includes
* Project root added micropython.cmake so that targets used by the MicroPython build can find includes
Note: pico-boilerplate projects must set this include path
The ../../../pimoroni-pico path was selecting the "pimoroni-pico" directory adjacent my "micropython" directory
However I was attempting to build against one in a different parent directory.
This resulted in the MicroPython modules including the wrong (old) header and exploding.
Phil Howard