Experimental branch where render() uses document fragments to build up content instead of strings
Need to test if performance is better on low-memory targets

- add enyo.Control.renderFragment which rendered directly into a node tree, using document fragments to collect children together and handle null tag nodes
- temporarily modify enyo.Control.render() to use the new renderFragment() call
- removed single-use methods enyo.Control.removeNodeFromDom, appendNodeToParent, insertNodeInParent
- enyo.Control.escapeHtml -> enyo.dom.escapeHtml
- enyo.dom.setInnerText: new method that uses best method to set safely set the text content of a node

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)
Add rendering via DOM API to renderInto as well.

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)