Use @nteract/tranforms

[lgeiger]

A initial stab at using @nteract/tranforms as a replacement for transformime in order to address #557, #560, #27 and #368 and support even more mimetypes.

Moved to a later time:

• Use @nteract/tranforms for inspector (the easy part 😄 )
• Refactor the following parts as React Components:
  • Result View probably powered by @nteract/display-area
    • Spinner component
    • Component for inline result
    • Component for multiline result
    • Component for rich output (I think we could even remove it and use the multiline output for simplicity and to have a more consistent appearance)
  • Watch Sidebar
    • Watch View component

There's quite a bit of work left to do and I don't know when I can get to it, so I'm parking it here 🚗
It would be super cool if someone wants to help with this effort 😇

[lgeiger]

I aimed a bit high in this PR 😄

In my last commit I took a different approach to the problem and used @nteract/transforms as a drop-in replacement of transformime without any refactoring.
This way we can iterate on this and can use all the awesome transforms right now:

Now we can easily add support for more mime types or even use @nteract/transforms-full if apm handles the install nicely (one transform has node-canvas as a native but optional dependency which may cause install problems).

I propose we go with this as is and move the refactorings into the future.

It would be cool if someone could take this branch for a spin since there may some minor style glitches I didn't caught.

[rgbkrk]

Classic message spec before v5. 😉

[BenRussert]

I think this is ready to merge!

This adds a great feature while reducing total lines of code! So much cleaner now.