Scaffold mockup for the playground

[davesnx]

Features

• Consume jsoo compiler and stdlib cmijs from melange
• Translate between re and ml syntaxes
• Add examples, on both syntaxes
• Syntax highlight
• Console execution (in worker, preferably)
• Read melange stdlib and react js files from _opam node_modules
• Highlight error in editor (underline)
• Reason-react + mount on page
• Store state into URL
• Store last entered code and syntax selection in local storage
• Copy to clipboard urls (adding notifications)
• The switch between Live/Generated code views is buggy: react example will fail if "live" is hidden, switching between both views loses state.
• Is there a way for refmt to not print implicit_arity attrs?
• "Console" panel should be scrollable
• "Console" panel should be reversed and scroll into view
• Syntax highlight flash on each keystroke (maybe debounce?)
• Add info about versions
• First load spinners (first load, editors and panels)
• Reformat with ocamlformat
• Compiling/Evaluating spinner
• React using latest ppx
• Fix reason-react example (Unbound module ReactDOMRe)
• Render warnings/alerts on Problems instead of Melange_compiler_libs__Warnings.Errors . In the console theres: Error (warning 109 [bucklescript-toplevel-expr-unit]): Toplevel expression is expected to have unit type.
• Bug: syntax selection doesn't work when there are errors. Repro: enter let t = <div />; in OCaml syntax, then switch to Reason and add a space. Nothing happens but expected is that code should be compiled.
• Clear console

UI

• Console and problems (scrollbars, sizes)
• Bug with resizes
• Tabs (live, generated output)
• Reason and OCaml toggle
• Drag effect
• Sidebar collapsible (icon, collapsed state)
• Examples dropdown
• Alert component
• Hide settings

Bugs

• Console prints crap
• When React example, logs don't show. (Probably because we eval on the main thread)
• When you remove React, the live should unmount.