imageformat plugins

[Alex Merry]

It occurred to me that KGuiAddons might not be the best place for the
imageformat plugins, and that they should maybe become their own
framework (either tier1 or tier4).

The only thing that relates the KGuiAddons library and the imageformat
plugins is that they are both to do with QtGui.  Each can be used
without the other just fine, and there is no particular reason why
someone wanting the library should want to install the plugins or vice
versa.

What do other people think about this?

Alex