Crumble UI touchups

[DeDuckProject]

Made some Crumble UI touchups:

• Fixed canvas blurriness which occurs on Retina display (and probably others)
• example circuits open as modal instead of inline
• html style extracted to CSS (the other CSS)
• Small improvements to styling (mainly buttons)
• main canvas size now dynamically calculated to fit screen (so no more scroll)

After:

Before:

[Strilanc]

I like the retina fixes and the dialog for the example circuits. But the other style changes seem sorta superfluous and appear to be breaking single-file-ness.

(Does hitting escape work for closing the dialog?)

[Strilanc]

This looks like it's breaking the fact that crumble compiles into a single HTML file (e.g. so that it can be written to stdout which is then piped into a file which is then opened with a browser).

Inline the styles into the HTML file.

[DeDuckProject]

Oh, cool. I didn't realize the inline style was intentional. Thought it only open as URL. will inline the styles, sure.

[Strilanc]

Why aren't we just using the default button style? I generally prefer to let each browser choose how widget should look.

[DeDuckProject]

Just a matter of taste, I guess. I can remove the button style, but still leave the flexbox such that at least they align properly.

[DeDuckProject]

I like the retina fixes and the dialog for the example circuits. But the other style changes seem sorta superfluous and appear to be breaking single-file-ness.

(Does hitting escape work for closing the dialog?)

I like the escape idea - will implement that + inline styles and revert the button opinionated styling.