#include <plasma/foo.h>
in headers in libplasma. this is important so that they can be used post-install by third party plugins, apps, etc.
also, changed Applet::loadDataEngine to just Applet::dataEngine and make it actually return the data engine; move the applets to using it. safer and fewer LoC
svn path=/trunk/KDE/kdebase/workspace/lib/plasma/; revision=670850
* move DataSource::Data to DataEngine::Data; this means consumers of DataEngine have no need to know about DataSource as a class
svn path=/trunk/KDE/kdebase/workspace/plasma/lib/; revision=666756
