Changes:
Refactor examples.py to add a new command line option to provide an update
tag.
Refactor examples.py to add new functionality to update the version of
mbed-os in the examples to a supplied tag.
Refactor examples.py to make cloning the example repos, updating their
mbed-os version and compiling, into library functions and move to a new
library module.
Refactor the format of the examples.json file to make it compatible with
both examples.py and update.py.
Refactor update.py so that examples are test compiled prior to updating.
Refactor update.py so that only examples tagged as auto-updatable and that
fully compile are automatically updated.
Anna Bridge