hex mode similar to chrome-devtools:
* Ctrl-Up/Down for R channel
* Shift-Up/Down for G channel
* Alt-Up/Down for B channel
* Up/Down treats the entire color as a hex integer e.g. #00f -> #010
rgb/hsl modes similar to chrome-devtools:
* Ctrl-Up/Down steps by 100 (alpha: by 1)
* Shift-Up/Down steps by 10 (alpha: by .1)
* Up/Down steps by 1 (alpha: by .01)
* PgUp/PgDn to switch format
* Tab to switch format when at the first/last input field