* Remove unnecessary load of /fg/css/client.css
* Replace dynamicLoader.loadStyles with dynamicLoader.loadStyle
* Replace Popup._injectStylesheet with dynamicLoader.loadStyle
* Remove unused global
* Validate document.body before use in loadScripts
This also fixes an issue where reject wasn't being passed to loadScriptSentinel.
* Validate document nodes before use in _getSiteColor
* Validate document.body before use in _getViewport
* Validate document.body before use in setContentScale
* Validate document.body before use in docImposterCreate