Default media-type or encoding for inserted file
************************************************

   When `C-c C-x C-i' (`mime-editor/insert-file') is pressed, tag
parameters for inserted file, such as media-type or encoding, are
detected by variable `mime-file-types'.

   When `C-u' is followed by it or parameter is not found from the
variable, it asks from user.  (When `C-u' is followed by it, detected
value is used as default value)

   If you want to change default value for file names, please change
variable `mime-file-types'.

 - Variable: mime-file-types
     Specification of default value of tag for file name of inserted
     file.

     It is a list of following list:

          	(FILE_PAT TYPE SUBTYPE PARAMS ENCODING
          	 DISPOSITION_TYPE DISPOSITION_PARAMS)

     Each elements of the list are following:

    `FILE_PAT'
          regular expression of file name

    `TYPE'
          media type

    `SUBTYPE'
          media subtype

    `PARAMS'
          parameters of Content-Type field

    `ENCODING'
          Content-Transfer-Encoding

    `DISPOSITION_TYPE'
          disposition-type

    `DISPOSITION_PARAMS'
          parameters of Content-Disposition field

     Example: Specify application/rtf as default media type for `*.rtf'

          (call-after-loaded
           'tm-edit
           (lambda ()
             (set-alist 'mime-file-types
          	      "\\.rtf$"
          	      '("application" "rtf" nil nil
          		"attachment" (("filename" . file)))
          	      )))