Since we are using the react-i18n babel loader plugin, useI18n can only
be used once per file. Also we have to remember to add the istanbul
ignore next comment each time we use it. By moving this to a common
file, it can be easily copied and pasted when a new submodule is
created and we don't have to remember the rules when calling it.
This replaces the ace editor with the monaco editor. It fixes quite a
few small paper-cut bugs and should be easier to add code completion
to in the future.
Many of the snippets are omitted but can be added back later if needed.
Otherwise, we have tried to preserve the existing look and feel as much
as possible.
David Lechner