adjusted notification call to new API.
checking if pref directory is present
added some debug output
fixed reading wrong file for version check.
read buildTree and build from version file

and deliver that info on retrieveVersion call.
improved "no internet" error message
prevent "upadte available" message on testing branch
skipping unsupported updates

Signed-off-by: Achim Königs <garfonso@mobo.info>