API and build change and fix summaries. Doc correctsions
and/or changes are not mentioned here; see the commit messages.
+2020 March 10; version 3.5.1
+ Add missing health check message types.
+
+2020 March 9; version 3.5.0
+ Added new wormhole send function: rmr_wh_call().
+
+2020 March 6; version 3.4.0
+ Add new wormhole state function: rmr_wh_state().
+
2020 March 5; Version 3.3.1
Correct several "bugs" identified by automatic code analysis.