Add palette picker/editor experiment

[riknoll]

Adds an experiment for use in pxt-arcade that lets you change your project's color palette!

Obviously this has gone through zero design iterations, so don't expect it to turn into anything other than an experiment anytime soon. Most of the palettes came from lospec.com via @jwunderl's pxt-color extension.

I went through and reordered the colors so that they are somewhat close to our default palette. This makes it so that the gallery sprites are still somewhat usable.

[jwunderl]

(in future, we could add support for importing using e.g. the .hex format output of lospec or gimp palette format but that's more on the 'possibly nice to have' side~)

[D4ngerKitty]

So I can no longer do this ?

[D4ngerKitty]

Why???

[riknoll]

@LucasMayhew this hasn't been pushed to beta yet. in the meantime, you can still override the palette in the usual way

[D4ngerKitty]

Okay

[D4ngerKitty]

any idea when it will be pushed like in the next few weeks or so

[D4ngerKitty]

Also it is soo hard to change the palette the old way

[D4ngerKitty]

I am sooo Hyped for this thing

[riknoll]

@LucasMayhew this is now in beta. you can turn it on like this:

1. Click the gearwheel menu
2. Click "About"
3. Click "Experiments"
4. Click "Change Color Palette"
5. Click "Go back" and wait for the page to reload
6. You should now see "Project Settings" in the gearwheel menu when you have a project open

[D4ngerKitty]

YES YES YES YES YES YES YES YES YES YES YES YES YES YES YES