avoid manipulation of text nodes on first repaint

[#56959632]

Error only occurred on Firefox.

An NS_ERROR_FAILURE: Failure related -txtSelection.node().getBBox().width /2) is happening when the charge symbols are rendered. If charge symbols are disabled, the model will load fine.

fyi:
First bad commit produced by git bisect:

commit 4a9cafca7241af04264be5afb778b9af97277c6f
Author: Stephen Bannasch <stephen.bannasch@gmail.com>
Date: Wed Sep 4 12:07:25 2013 -0400

repaint MD2D render when initialized

Otherwise the model calls into the renderer
before variables like objects are setup.