Update Model Info

1. Improve navigation to the Model Info page by adding a tab between Patterns and Extensions named "Model Info" which links to the Model Info page.
2. In http://hl7.org/fhir/us/qicore/STU4.1.1/patterns.html#fhir-and-cql , create a new <h4> sub-section titled "Model Info" within section 3.1 before the paragraph which begins with "To use CQL with FHIR.."
3. Update the shaded block "using QICore version '4.2.0' " to use the correct version number to match the updated Library.version
4. Update the FHIR Library resource which embeds the modelinfo for "using QICore" in CQL; http://hl7.org/fhir/us/qicore/STU4.1.1/Library-QICore-ModelInfo.html 
5. In the new Model Info sub-section, add text to explain situations where more than one CQL "using <model>" line may be needed based on which US Core and other profiles are included within the QI-Core modelinfo.
6. Update the links for the CQF Common IG to point to http://fhir.org/guides/cqf/common/history.htmlinstead of the build version.

For example, the QICore model info (version 4.1.1) does not contain the US Core Provenance profile.  If CQL logic needed to retrieve a Provenance resource, the CQL would need "using USCore version '3.1.1' " in addition to "using QICore version '4.1.1' "

Since the QI-Core IG does not currently contain the model info for US Core in a separate Library from the QI-Core model info Library, and the US Core IG also does not contain a Library resource for the US Core model info, add text to say something about where to find other model info Library resources: Reference http://hl7.org/fhir/us/cqfmeasures/StructureDefinition/modelinfo-library-cqfm and suggest a search [Base]/Library?type=model-definition to find Model Info files published in a FHIR server.

Consider adding a Library to QI-Core IG for the US Core model info (for US Core 5.0.0).