Fix haskell-interactive-switch reference (fixes #298)
Fix indent/interactive help message (closes #297)
Make questions use read-event, so they can be C-g'd properly
When GHCi process bails, prompt to open the process log (fixes #238)
Nicer to read process-log output
Generalize error parsing into one function using haskell-compilation-error-regexp-alist

This helps haskell-process to support the ferror-spans syntax, and
also the error jumping in haskell-interactive. My implementation of
-parse-error is lame, but it's general, anyway.

Ping @hvr
Another extension enabling case