Add solid-devtools panel

[thetarnav]

Closes #117

It kinda works

There are a couple of issues to resolve though:

• solid-devtools will work only with the latest version of solid—I'm constantly adding small things to solid that the debugger going to require to work correctly.

• the debugger should only be loaded when the devtools are open—I don't consider it stable enough to have it running constantly.

• I might need to add an option to the overlay package for it to be embeddable in an iframe. It is very likely that the devtools overlay and the user's app will mess with each other if it isn't separated.
  Not sure how can I go about doing that though. Iframes aren't really build-tool friendly.

• if running the user's code throws an error, the render() root doesn't get disposed of on the next code change. Leaving it in the devtools UI. Likely that the debugger just needs to be cleared on every code-change.
  now roots get cleared with each code update

I've also made that the chii devtools are used on all chromium browsers, not only chrome itself.