support empty strings an false in Kwf_Config::getValue

before always null was returned
don't check baseUrl on cli
also set empty baseUrl

else Kwf_Setup::getBaseUrl would try to detect it automatically
use component_id instead of db_id because we have data objects anyway

this should be more correct than before.
db_id was used because previously we *only* had db ids and no data objects
Merge remote-tracking branch 'vivid/master'