patch for UI Options

[Valles, Heidi]

hi all,

I've added a patch for UI Options. The Jira url is http://issues.fluidproject.org/browse/FLUID-3743

This patch 1) adds previewTemplateUrl as an option to UI Options 2) adds a unit test that checks the default url is set, as well as a custom url 

Could someone please review my changes? The number of lines are few.

thanks,
heidi

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Heidi Valles
Accessible Software Developer
Inclusive Design Research Centre, OCAD University