ADDED missing callback handler in the SetupStepHandler (just for the API).

Signed-off-by: Michael Grammling <m.grammling@external.telekom.de>
Merge branch 'master' into huebinding

Conflicts:
	bundles/config/org.eclipse.smarthome.config.setup/src/main/java/org/eclipse/smarthome/config/setup/SetupStepHandler.java
	bundles/config/org.eclipse.smarthome.config.setup/src/main/java/org/eclipse/smarthome/config/setup/internal/SetupStepProcess.java


Signed-off-by: Oliver Libutzki <o.libutzki@external.telekom.de>