Add w3m-haddock.el

One can use w3m for browsing haddocks docs. This module makes it
format the documentation more nicely, supports jumping to an
identifier within a package, and auto-syntax highlights buffers that
look like source buffers.
Support continuations in the process loading
Use marker instead of regexps in haskell-interactive-mode prompt

Instead of searching for a prompt with a regex, just use a marker
starting at "> |".

@hvr might be of interest.
Add haskell-process-reload-devel-main interactive command
Add multi-line support in REPL

@hvr might be of interest.
Remove accidentally left in font-lock experiment
Add haskell-w3m-open-haddock
Add customization setting for header color
More liberal source match