Options ui (#222)

* wip

* Commenting stuff to keep the build happy

* Revealing sections

* Custom select elements & more form work

* Range input styles

* Text fields with inputs do the right thing

* Safari & Firefox fixes

* Large compress select

* oops

* MozJPEG options updated

* OptPNG options

* These asserts weren't true

* Generic options

* WebP options

* Hiding "edit" when "original image"

* Download icon

* Copy setting button - still not happy with this

* Progress indicator

* Loading icon enter/exit anim

* Preventing controls going under options

* Ahh so that's what was causing scrolling

* Ahh so that's what was causing outlines

* Simplifying range styles and fixing cross-browser

* Processing custom element styles

* Get precision from step by default

* I don't know how or when this happened.

* Don't need that many steps

* Avoid having an element that covers the pinch zoom

* Preventing overlap with zoom controls

* Prevent ts warning

* Fixing spinner position

* Simplifying FileSize

src/components/Output/custom-els/TwoUp/styles.css

@@ -52,7 +52,7 @@ two-up[legacy-clip-compat] > :not(.two-up-handle) {
   height: calc(var(--thumb-size) * 0.9);
   background: var(--thumb-background);
   border: 1px solid rgba(0,0,0,0.2);
-  border-radius: calc(var(--thumb-size) * 0.08);
+  border-radius: var(--thumb-size);
   box-shadow: 0 1px 4px rgba(0,0,0,0.1);
   color: var(--thumb-color);
   box-sizing: border-box;