Fix synopsis() so it can handle binary module files.

Fix synopsis() so it can handle binary module files.
Avoid ever using popen on Windows, since it's broken there.
Factor out the business of getting the summary line into splitdoc().
Use the modulename() routine in inspect.
Show all members of modules and classes rather than filtering on leading '_'.
Small typo and formtating fixes.
Don't show warnings when running "pydoc -k".