Add httpTimeout setting to options

Bump for v2.9.4 release

Adds httpTimeout to options.

Fix getComputedStyle issue

v2.9.3

Bump version to 2.9.3 to fix min file built wrong.

Release 2.8.0

Fixes for:

• Changing class names on SVG nodes where the node's class was tainted by being animated (and those being a SVGAnimatedString. From tsayen#250 by https://github.com/eddydg
• Error fetching the file extension when a resource URL has a query string that has a . character in it. From tsayen#285 by https://github.com/CG-man

Bump dev dependency on mocha to version 6.1.4 to fix vulnerability warning