When get.py is run in a script the percent-update printouts shown while
downloading the toolchain end up as 100s to 1000s of lines in log files.
When stdout is not a terminal, avoid printing these percentages and
shrink logfiles significantly. Errors/etc. are still reported as normal.
Fixes#171
Under Windows, it is very hard to make a symlink and by default git won't
make one to the Arduino API directory, causing annoying build errors.
Avoid the issue by duplicating the ArduinoAPI directory explicitly and using
CI to verify that there are no differences between the two.
