Release MH-E version 8.6.

Release MH-E version 8.6.

* NEWS, MH-E-NEWS: Update for MH-E release 8.6.

* mh-e.el (Version, mh-version): Update for release 8.6.

* mh-comp.el (mh-insert-x-face): Ensure that mh-x-face-file is a
string before trying to use it (closes SF #474).
(mh-bare-components): New function to create a temporary initial
components file; replaces mh-find-components. Improve the temp folder
and file names as per a suggestion from Bill Wohler. Also address
XEmacs compatibility issues: use mm-make-temp-file instead of
make-temp-file, and only pass one argument to delete-directory.
(mh-edit-again, mh-send-sub): Use mh-bare-components instead of
mh-find-components (partially closes SF #468).