Review changes in Gramps 5.2

[DavidMStraub]

As mentioned in #424, a couple of changes in Gramps 5.2 need review to see if we can add a corresponding feature or can simplify our code:

• Add support for open spans.
• Add strikethrough and superscript/subscript support.
• Add new gender option of "Other".
• Add citations to event references.
• Add coordinates format with description. Fixes #11248
• Remove the note type 'Html code' for notes. Fixes #12184
• Add a new person filter rule 'HasAddressText'.
• Add 'HasAttribute' filter rule to repositories, sources and
• citations. Fixes #9845
• Add new note type of "Analysis".
• Add Stillbirth as pre-defined event type. Add Stillbirth as a
• fallback for both Birth and Death events.
• Change "death cause" to "cause of death".
• Add Godparent as event role.
• Replace TEMP_DIR by tempfile object.
• Fix Place.get_text_data_child_list
• Note LINK support for merge of other objects.
• Note LINK support for deletes of other objects.
• Support Note LINKS as backlinks.
• Do not strip checksum of media object in private proxy.