add an option to select pointer acceleration profile
Allow the selection of one out of three porfiles: diabled, flat, adaptive. The last one is adaptive to the poimter movement, and our previous default behavior. Fixes: https://bugs.launchpad.net/bugs/1522295, https://bugs.launchpad.net/bugs/1524145, https://bugs.launchpad.net/bugs/1528109.
Approved by PS Jenkins bot, Daniel van Vugt, mir-ci-bot, Kevin DuBois.