Re: Merging Finder into package mechanism

[Chong Yidong]

I've checked in a change to make Finder set package--builtins rather
than its own finder-package-info variable.  No Finder functions have
been deleted, but the entries in the *Finder* buffer now generate
package-menu buffers instead of *Finder Category* buffers; and thus
*Help* buffers from `describe-package' have replaced *Finder Package*
buffers.

This also means that `M-x list-packages' now contains a long list of
built-in packages, generated at compile time, instead of the short
hardcoded list we had before.  I've added "Package:" headers to
numerous Lisp files to group them into sensible built-in packages;
if I've missed any, let me know.

Searching elpa packages by keyword is not implemented yet.