Log Message:
Update to 2.6.0.  The list of changes since the previous stable version may
be incomplete, but couldn't find anything better:

libbonoboui 2.5.3
	* bugs fixed
		+ toolbar/dock destruction crasher (Michael)
		+ unused arg cleanup (Fernando Herrera)
	* featurelets
		+ BonoboWindow cleanup (Arvind Samptur)

libbonoboui 2.5.2
	* bugs fixed
		+ require the right gtk+ (Jason Leach)
		+ AIX portability (The Written Word)
		+ svg icon image size (Sergey V. Udaltsov)
		+ status bar grip problem (Michael)
		+ control 'activate' signal (Federico, JP)
		+ memove not strcpy for overlap (JP)
		+ dock size allocation problem (Michael)
	* featurelets
		+ status bar packing improvement (Alexander Larsson)