Make errors expanded by default
Make showing debugging tips an option
Option to automatically chmod .ghci files that GHCi ignores

.ghci files are a convenience facility. GHCi decides out of security
concerns that it will simply ignore convenience files. For an
interactive application, this is pretty stupid. The better approach
is the approach that Emacs takes, which is to prompt the user and
allow them to decide conveniently.

This patch collects all files that GHCi warns that it has ignored into
a list, the user is given a message like this:

GHCi is ignoring: /home/chris/foo (run M-x haskell-process-unignore)
GHCi is ignoring: /home/chris/foo/.ghci (run M-x haskell-process-unignore)

When they run `M-x haskell-process-unignore', they get:

Set permissions? /home/chris/foo/.ghci (y, n, v: stop and view file) y
Permissions command: chmod 700 /home/chris/foo/.ghci

This allows the user to edit the permissions command per file, if
desired, or they can just hit RET. They also have the option to stop
this procedure and view the file first.

At the end, it prompts the user to restart the process for the
changes (if any) to take effect.

This is not portable to Windows. There apparently is some command for
Windows for setting permissions but it's difficult to know how
reliable it is and I don't have a Windows machine to test on. Instead,
I include a note in the function for Windows-using Emacs hackers to
further extend it.

@hvr might be of interest.
Use && instead of ; because this works on Windows, too (refs #232)