Code review comment for lp:~andreas-pokorny/mir/add-option-to-disable-acceleration

(1) Naming needs clarification per above.

Manual testing results:

(2) Surprisingly --mouse-acceleration=none does not fix bug 1528109 but --mouse-acceleration=constant does. Have we misinterpreted the "none" mode? Should it be removed in favour of constant mode with no bias?

(3) The --mouse-acceleration option is missing from some servers (mir_proving_server) so still not helpful to me. I guess it or something like it needs to be promoted up into libmirserver default config at some point.