mm-decode.el (mm-inline-media-tests): Add text/x-sh.

mm-decode.el (mm-inline-media-tests): Add text/x-sh.
gnus-art.el (gnus-mime-inline-part): Use mm-display-inline rather than mm-insert-inline to insert inline part: this respect mm-inline-media-tests displayers.
mm-view.el (mm-display-shell-script-inline): New function.
mm-decode.el (mm-inline-media-tests): Add x-shellscript and x-sh.
mm-uu.el (mm-uu-type-alist): Add org block.
 (mm-uu-org-src-code-block-extract): New function.
mm-view.el (mm-display-org-inline): New function.
mm-decode.el (mm-automatic-display): Add text/org.
mailcap.el (mailcap-mime-extensions): Add .org.