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.