Catch StopIteration exception for python 3.7 compatibility.

components/iscesys/Parsers/rdf/read.py

@@ -46,10 +46,13 @@ from .reserved import glyphs
 def _unwrap_lines(gline, wrap=glyphs.WRAP):
     """given a read_stream() generator, yield UNWRAPPED RDF lines"""
     while True:
+        try:
             line = next(gline)
             while line.endswith(wrap):
                 line = line[:-len(wrap)] + next(gline)
             yield line
+        except StopIteration:
+            return
 
 ## file name --> unwrapped lines
 # \param src A file name