Remove references to the abbreviations for population criteria, in favor of explicit reference to the population criteria names throughout. Also recommend alignment with this approach in Bonnie, eCQM Measure Logic & Guidance, and the Blueprint. Updated diagrams (2 process, 2 population flow) as reviewed by CQI WG April 24, 2020 and add descriptive text about usage. Also update the CQL definitions conformance requirements (#8) and population criteria definitions.