Specify colors by url parameter

[slimbuck]

Fixes: #329

This PR:

• adds ability to overwrite selectedClr, unselectedClr and lockedClr the way bgClr can
• colors are specified as an array, for example &selectedClr=0.8,0,0,0.5
• also deleted some legacy classes from config and code

[willeastcott]

Camel-case in URL params bothers me for some reason. But you're presumably doing this because they match up with JS property names?

[slimbuck]

Yep

[willeastcott]

I mean, don't want to be annoying here, but I'd almost prefer a Map of nice URL params to internal property names. And then we can proudly document them.

[slimbuck]

We could do, but:

• this feature shouldn't be needed in the near future when we introduce document format
• if we have a map we'd have to document it somewhere. currently there is just one reference and everything shares it

[willeastcott]

OK, I shall bow to your supreme authority on this occasion.

[slimbuck]

Which format would you prefer for url params, kebab-case? I might be able to do an auto-case-conversion...

[willeastcott]

Yeah, I ❤️ kebabs. 😋

[slimbuck]

I've added support for all values to specify either case, bg-clr or bgClr 👍🏻