Ignore short METS object ids (OBJID)

Visual Library uses OBJID="1" (sometimes also "2", "3") for all records.
Ignoring such short OBJID helps when importing from Visual Library.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Handle files with mets:mptr and physical pages

In the old code, physical pages were not handled if there was a mets:mptr
entry. This was bad when importing from Visual Library.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Avoid endless recursion

Signed-off-by: Stefan Weil <sw@weilnetz.de>
tca: Fix typo in code

Signed-off-by: Stefan Weil <sw@weilnetz.de>