libwnck soname bumps

[Matthias Clasen]

This is a somewhat late notice about a soname bump in libwnck that
happened last night. If you haven't rebuild your dependent packages yet,
you may want to hold off a little longer, since there is another soname
bump coming down the pipe tonight. This one is for adding padding that
will help avoiding future soname bumps. 

Sorry about this, but you all signed it with
WNCK_I_KNOW_THIS_IS_UNSTABLE...

Matthias