New: halfway commit for removing jQueryUI dependency

-Replaced $.ui.keyCode shortcuts with the integer values they represent.

-Replaced jQueryUI slider with <input type="range">

-Moved on('slide') to on('input'); on('change') remains and on('stop') is no longer needed

-Changed references from .slider('value') to .val()

-Added parseInt() checks to both .on('input') and .on('change') as slider returns value of type string rather than value of type number

-Reposition slider to line up with zoom-level label
Fixed: various issues in process.py

-changed DivaConverter to use **kwargs

-used string formatting instead of concatenation

-removed VImage check that I thought I proved was relevant but was completely incorrect
New: grid slider ported from jQueryUI to HTML5

-Fixed CSS so toggling between grid and regular works fine

-Changed grid slider to HTML5 slider

-Made same changes in last commit with zoom slider to grid slider
New: jQuery UI removed from utils.js

-Converted canvas.js slider to HTML5 <input type="range">

-Removed jQueryUI copy from utils.js as it seems that nothing depends on it anymore.
Merge branch 'develop' of https://github.com/ddmal/diva.js into develop