GPII-1014: Replace the slider adjuster for cursor size with plus/minus text field adjuster

The bug report: http://issues.gpii.net/browse/GPII-1014

This pull request also upgraded the infusion library to be in sync with the latest master: https://github.com/fluid-project/infusion/
Discuss with Dana in the channel: https://botbot.me/freenode/fluid-work/2014-11-24/

The decision is to use "larger" and "smaller" for all steppers.