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.
Thanks to Nestor from Logitech for providing me this device.
This mouse has two buttons on the left, currently mapped to 8 (bottom
button) and 9 (top button).
Note: setting bit 1 of register 01 does odd things in KDE. I looked in
SetPoint 6.61.15 and could not find an option for "Side Scroll",
perhaps it is not applicable here?