Add default Hlt1 filter in Hlt2
Resolves #735 (closed)
Adds an Hlt1 filter to every Hlt2 line. The filter can be modified by binding the property code
of get_default_hlt1_filter_code_for_hlt2
in python/Moore/lines.py
Merge with Allen!1492 (merged) and MooreOnline!374 (merged)
Edited by Daniel Charles Craik