device-manager-evdev: handle tablet axis motion before button and tip events

Some tablets have a noticable pointer jump on tip down/up, causing unintended lines during drawing. Likewise, a button event may have an axis update that we currently ignore. libinput provides tablet axis events only if no other state changes, the client must instead get the current axis data from the tip/button event. So let's do this, process the event axis data during tip/button as well.

A libinput recording to reproduce is the 'dots.yml' in https://gitlab.freedesktop.org/libinput/libinput/issues/128

Fixes #289 (closed)