add flags to enable/disable all editor (toolbar) action sets
Merge pull request #614 from kossebau/makeEditorUIConfigurable

add flags to enable/disable all editor (toolbar) action sets
deduplicate tool creation code in Tools
Merge pull request #615 from kossebau/lessCodeDuplicationInTools

deduplicate tool creation code in Tools
Fix property removedProperties of ops.OdtDocument.signalMetadataUpdated

was passed as removedProperties.attributes: !string
instead of    removedProperties: !Array.<!string>

also
* reuse initial spec variable
* only deep clone opspec.setProperties, as removedProperties is cloned by
  opspec.removedProperties.attributes.split(',') already
Init removedPropertiesArray to null, is understood by OdfContainer.setMetadata
Remove dead code from ops.OpUpdateMetadata
Add gui.MetadataController
Merge pull request #608 from kossebau/metadataController

add gui.MetadataController (+related fixes)
Add SessionBackend abstraction

hides away any assumptions about server class structures from the Editor class
Remove option to configure the member id in local edit mode