Replace webpack with modd (2nd try)

You are right, the webpack configuration works right now and may be easier to kick off because most frontend devs will have installed node and npm anyway. So, let's postpone the question of the best build system to a later time.

As a workaround for the poor formatting of compiler messages there is already a supplemental modd.conf file, so that modd can be run alongside webpack just for the compiler messages.

For future reference let me sketch my reflections on that topic so far:

What I don't like about webpack is...

It pulls in a lot of files (currently 46M in 6661 files).
It's hard to configure.
It's hard to tweak for colorful compiler messages.
At least for development builds we don't need any of it's module bundling functionality. All we need here is: call the Elm compiler, copy some files, simple http serving with live reload.

On the contrary, a production build process may profit from webpack's abilities.

Alternatives (for development builds):

modd & devd as discussed in this PR and in #33
elm reactor (not sure if it works currently with out project)
tomekwi/elm-live
Probably other npm based solutions
Tell people how to invoke elm compile and let them choose a dev server on their own.

participateapp / web-client

Replace webpack with modd (2nd try) #58