XDG Compliant user package tree -- doc updates.
This updates the documentation to reflect the new location for user
(early) packages.
* PROBLEMS: Add section about early-packages locations.
* README.packages: Update the text relating to user packages.
* etc/sxemacs.1 (FILES): Ditto.
* info/lispref/packaging.texi (The User View): Update.
* info/new-users-guide/custom2.texi (Init File): Typo fix.
* info/sxemacs-faq.texi (Q5.3.3): Ditto.
* info/sxemacs/cmdargs.texi (Command Switches): Add
-user-pkgs-directory.
* info/sxemacs/startup.texi (Startup Paths): Update for current
reality.
Signed-off-by: Steve Youngs <steve@sxemacs.org>