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/
jshint error "'$' is defined but never used." There may be other errors too. You can run `grunt` to fun jshint and jsonlint