Use CIE L* (psychometric lightness) mapped from luminance
(assumes uniform luminance for R, G, and B channels)

Predefined colors are assumed to be LED values

This has the side effect of lengthening the low time proportionally,
to a total of 417 ns longer than necessary.  This does not appear to
have any observable negative impact.

By doing this and eliminating mDNS, we save loads of RAM.

Also fix possible crash when changing presets

Also simplified sparkle pattern memory

Includes slight refactor of pattern factory

- New definitions can be delivered via MQTT
 - Includes extensible pattern class for new preset types

By doing this and eliminating mDNS, we save loads of RAM.

Also fix possible crash when changing presets

Also simplified sparkle pattern memory

Includes slight refactor of pattern factory

- New definitions can be delivered via MQTT
 - Includes extensible pattern class for new preset types

Changed refresh rate to 4 Hz to better visualize animations

Includes terminal LED simulator