The `__future__` we relied on is now, where the 3 specific things are
all included [since Python 3.0](https://docs.python.org/3/library/__future__.html):
* absolute_import
* print_function
* unicode_literals
* division
These import statements are no-ops and are no longer necessary.
Add a general heuristic that options ending in -path expect an argument.
Remove such options from the explicit is_arg_param list and sort it to simplify maintenance.
Recognize -target-sdk-version.
The utils/dev-scripts/at-to-filelist, utils/dev-scripts/split-cmdline and utils/build-parser-lib scripts needed to be reformatted with the black tool to agree with the linter.
For details see the comment in split-cmdline
I put this under a new directory utils/dev-script because we have so much stuff in utils already.
Other, similar scripts can then be added in dev-scripts as well.
