allow users to pass parameters through the url

[jwildfire]

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[jwildfire]

Added URL query string support for 'renderer' (or 'r') and 'version' (or 'v'). 'renderer'/'r' can be a string or a number. If a number is provided, the index value of cat.config.renderers is used to select the renderer. A few sample URLs below:

https://rhoinc.github.io/CAT/?r=aetimeline //draws aetimeline with master branch
https://rhoinc.github.io/CAT/?renderer=aetimeline // same as above
https://rhoinc.github.io/CAT/?r=aetimeline&renderer=hep-explorer //'renderer' takes priority. hep-explorer is drawn
https://rhoinc.github.io/CAT/?r=safety-outlier-explorer
https://rhoinc.github.io/CAT/?r=safety-outlier-explorer&version=noverlap // shows feature branch
https://rhoinc.github.io/CAT/?r=0 //draws the 1st renderer
https://rhoinc.github.io/CAT/?r=4 //draws the 5th renderer