They don't make it into the final image so building dependencies wastes
compute time without any real benefit.

Fix PermissionError

Add example notebook for ihaskell-gnuplot

stack.yaml: bump resolver to lts-18.7

Rewrite Docker image

If anyone needs this flag, they should be able to just do
--ghc-options='-dynamic'. Instead of removing it, we could also hide it
behind a Cabal flag

Bump stack resolver

Update some example notebooks

replaceOutput runs without flickering the GUI

Update some example notebooks to the latest notebook version, so that
when they start, Jupyter doesn't immediately update them and mark them
as changed.

Also replace the fake diagrams test notebook with a real diagrams test
notebook. The fake diagrams test notebook was actually the charts test
notebook.

Also export `OutputMsg` constructors so that users can call
`setField` on an `OutputWidget` to write their own `replaceOutput`
functions.

Updated sample widget Notebooks