Remove the -moz- and -o- @keyframe prefixes.
Add a huge chunk of code to overrideBackgroundImage.

It's nearly complete. It adds the right class but the regular
expression I have doesn't work to remove the existing background
class.
Move the override functions to the bottom of $.getJSON().
Fix typo and use single quotes in setBackgroundImage.
Use single quote and remove brackets on while loop in getUrlParameters.
Add mechanism to replace 'bg-' class set by getRandomBackground.
Edit 'else if' in overrideBackground.
Set up main variables in overrideQuote.
Remove 'else if' comment from background override.
Add usage details to overrideBackgroundImage.
Remove unnessecary 'else' from background override.
Consolodate the background & quote retrievers into one function.
Fix typos in comments.