Feature request: multiple built-in color combinations

[MatthewStanciu]

People may not like the default colors given by purduehackers/time, but nobody wants to spend hours playing with colors to find the right combination. We should do this instead, and include 3-4 default combinations.

Usage:

const lt = new LightningTime({ colors: 'default' })
// new LightningTime() with no args is still accepted
const lt2 = new LightningTime({ colors: 'alt1' })
// ...
const ltx = new LightningTime({ colors: { boltColors: [0, 161], ... } })

bonus: give them cute names like "ocean aurora" or some shit