Panel plugins have a fixed size in trunk

[Nick Schermer]

>From now on the plugin size is fixed in trunk. This means the plugin
cannot increase the panel size anymore and will be cutoff when it is
bigger.

I know some developers are not going to like this, but really, you
have to live with it. The reason is easy: some plugins use the panel
size to, for example, calculate the icon size. If an other plugin
increases the real size of the panel, this technique becomes useless.
Using the allocated size might result in loops (ask Samuel ^_^), so
this is the best solution for (almost) everyone.

Greets,
Nick and Jasper