Fix up the project.json files for CoreFX build rc2-23922.
Fix up the project.json files for CoreFX build rc2-23922.

- ProjectModel uses AssemblyLoadContext which is only available in netstandard1.5. Moving ProjectModel and all its dependencies up to netstandard1.5.
- Work around our dependencies still being on old CoreFX builds by hoisting System.Runtime.Serialization.Primitives, System.Private.DataContractSerialization, System.Linq.Expressions, and System.Xml.XmlSerializer references to the current version.

janvorli/core-setup,wtgodbe/core-setup,joperezr/core-setup,crummel/dotnet_core-setup,karajas/core-setup,cakine/core-setup,ravimeda/core-setup,gkhanna79/core-setup,ellismg/core-setup,chcosta/core-setup,zamont/core-setup,zamont/core-setup,joperezr/core-setup,weshaggard/core-setup,chcosta/core-setup,karajas/core-setup,vivmishra/core-setup,MichaelSimons/core-setup,vivmishra/core-setup,steveharter/core-setup,rakeshsinghranchi/core-setup,ellismg/core-setup,schellap/core-setup,zamont/core-setup,crummel/dotnet_core-setup,ellismg/core-setup,steveharter/core-setup,janvorli/core-setup,karajas/core-setup,chcosta/core-setup,ramarag/core-setup,weshaggard/core-setup,janvorli/core-setup,ramarag/core-setup,steveharter/core-setup,chcosta/core-setup,gkhanna79/core-setup,ravimeda/core-setup,joperezr/core-setup,joperezr/core-setup,ellismg/core-setup,schellap/core-setup,gkhanna79/core-setup,rakeshsinghranchi/core-setup,ramarag/core-setup,weshaggard/core-setup,ericstj/core-setup,cakine/core-setup,wtgodbe/core-setup,cakine/core-setup,MichaelSimons/core-setup,ravimeda/core-setup,zamont/core-setup,wtgodbe/core-setup,schellap/core-setup,gkhanna79/core-setup,ramarag/core-setup,ravimeda/core-setup,vivmishra/core-setup,MichaelSimons/core-setup,cakine/core-setup,vivmishra/core-setup,vivmishra/core-setup,ericstj/core-setup,ericstj/core-setup,ericstj/core-setup,wtgodbe/core-setup,ravimeda/core-setup,crummel/dotnet_core-setup,weshaggard/core-setup,ellismg/core-setup,ramarag/core-setup,crummel/dotnet_core-setup,cakine/core-setup,rakeshsinghranchi/core-setup,MichaelSimons/core-setup,rakeshsinghranchi/core-setup,steveharter/core-setup,chcosta/core-setup,chcosta/core-setup,weshaggard/core-setup,ellismg/core-setup,MichaelSimons/core-setup,ericstj/core-setup,janvorli/core-setup,gkhanna79/core-setup,wtgodbe/core-setup,joperezr/core-setup,crummel/dotnet_core-setup,vivmishra/core-setup,karajas/core-setup,cakine/core-setup,MichaelSimons/core-setup,janvorli/core-setup,steveharter/core-setup,ravimeda/core-setup,janvorli/core-setup,ramarag/core-setup,zamont/core-setup,crummel/dotnet_core-setup,rakeshsinghranchi/core-setup,karajas/core-setup,wtgodbe/core-setup,rakeshsinghranchi/core-setup,schellap/core-setup,steveharter/core-setup,karajas/core-setup,schellap/core-setup,gkhanna79/core-setup,schellap/core-setup,zamont/core-setup,weshaggard/core-setup,ericstj/core-setup,joperezr/core-setup