solaar-cli: fix argument parsing in Python 3 again

Fix from e3a887f36cc6ec7ddb3760d31b47dacb6931a7eb, this got removed
in:

    commit 3b75b6997008a6e0479cd324cc18ae0d79b279af
    Author: Daniel Pavel <daniel.pavel@gmail.com>
    Date:   Fri Aug 9 12:25:47 2013 +0200

        merged solaar-cli functionality into main solaar binary
solaar: add --hidraw option again

This options allows the devices list to be restricted which got removed
in:

    commit 3b75b6997008a6e0479cd324cc18ae0d79b279af
    Author: Daniel Pavel <daniel.pavel@gmail.com>
    Date:   Fri Aug 9 12:25:47 2013 +0200

        merged solaar-cli functionality into main solaar binary

solaar-cli is still busted, but since it is deprecated, it's probably
fine.
Fix wrong register name for illumination (hidpp10)

Broken since 9a2a28e, this causes a lot of exceptions for every move.
Fix missing reprogrammable keys

The assumption that the Features IDs are in increasing order does not
hold. This causes the feature check for REPROG CONTROLS (1B00) to fail,
therefore remove the micro-optimisation.

While at it, rename variables and document the functions better.
Merge pull request #118 from Lekensteyn/fixes

Regression fixes: --hidraw option, python3, hidpp10