Correct a bug where if the first archetype displayed fails, the display language can't be worked out.
Correct parser for deal with the metadata top line of the archetype. This now scans properly. See the following test archetypes in openEHR/adl-archetypes on GitHub.

openehr-TEST_PKG-WHOLE.parent_with_uid.v1
openehr-TEST_PKG-WHOLE.child_with_uid.v1

openehr-TEST_PKG-WHOLE.parent_with_uid_and_other_metadata.v1
openehr-TEST_PKG-WHOLE.child_with_uid_and_other_metadata.v1