Update dependencies to net45, IM 5.3, and Json 10.0.1

[Tratcher]

No code changes, it's all mechanical dependency management:

• Version 4.0 says Dependency Newsoft.Json >= 9.0.1, but is it 10.0.0.0? #215 we'd updated the Json dependency in packages.config but not in the nuspecs.
• Updating IdentityModel to a current version (5.3.0)
• nuget won't install it with net framework 4.5 #171 A prior IdentityModel preview required updating net451, but net45 support was added back before it released. We've gotten several complaints about the nuget upgrade experience breaking for apps targeting net45 so we're going to revert our dependency from net451 back to net45.
• Microsoft.Owin.Security.ActiveDirectory 4.0 does not work after update #178 IM 5.x restructured their packages and we forgot to add one of the new dependencies to Microsoft.Owin.Security.ActiveDirectory

[Tratcher]

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