Added `load-grunt-tasks` to the Gruntfile to make it easier to understand.
Added support for tickmarks and hid the overflow of the track fill so that it retains the round shape.
Added support for negative track fills.
Added support for Bootstrap striped backgrounds.
Re-organised layout.
Updated tasks.
Created a library for local mixins and used them to create new handle stylers based on the Bootstrap buttons.
Added a force-update function that emits update events so that a slider-driven UI can be initialised correctly.