bug#7406: 24.0.50: new variable needed `imagemagick-pseudo-types'

[MON KEY <monkey@sandpframing.com>]

(defvar imagemagick-pseudo-types
 '(CANVAS CAPTION CLIPBOARD FRACTAL GRADIENT HALD HISTOGRAM LABEL MAP MATTE NULL
 PLASMA PREVIEW SCAN PRINT RADIAL_GRADIENT STEGANO SCANX TILE UNIQUE VID WIN X
 XC))

`imagemagick-types' return value includes all of the above.
Most of these aren't _types_ of images.

While it is no doubt useful that these be specified (b/c any future
extensions/interop between
Emacs and Imagemagick will most likely need them) it will only cause
head scratching
for users not familiar with IM.

Indeed, I'm moderately familiar with IM and still can't help but find
the naming of some of these "types" offensive... and they really
shouldn't  occur within the return value for `imagemagick-types' --
they are "other". This distinction should be made explicit now not
later.

--
/s_P\