Make navigate-imports a bit more useful in absense of import list

If there is no import list it will try to jump to one blank line after
the module header.
Strip out M./S./L. typical module prefixes for suggestion functionality
Better "not in scope" detection

This ignores the “type constructor or classtype constructor or class” stuff.
Support god-mode on SPC key
Don't use replace-regexp to appease make check
Allow whitespace before settings.
Check for build/install as substring

Sometimes you might run C-c c (cabal command) and then type build
--ghc-options=-fforce-recomp, but then it wouldn't've been treated as
a build process and compiling/messages wouldn't be handled
specially. So this patch just checks for the prefix "build" or
"install" and then ignores anything afterwards.