merge IControllable into IProcessComponent, remove IControllable

Signed-off-by: Christian Lüthold <biocodr@gmail.com>
IProcessComponent.start() doesn't return a IPC interface anymore as it
makes no more sense

Signed-off-by: Christian Lüthold <biocodr@gmail.com>
updated and corrected JavaDoc of IProcessComponent

Signed-off-by: Christian Lüthold <biocodr@gmail.com>