Add metadata interface.
Define the interface for metadata more exactly.
Put the binaryMeta query also into the metadata interface.
Update the metadata interface.
Add slash.
Implement MetadataService interface.
implement MetadataService rest interface
get rid off the binary meta data rest resource of QueryService
Get rid off unused metadata methods.
use the docname rest api from metadata rest service
switch to docnames for metadata interface
remove the last metadata methods from query service
Merge branch 'metadata_interface' into develop

fixes #117