Added compile of the shared files

Added in the project.json a buildOptions to include in the compilation all the .cs files that are part of the Shared folder.

For now, there is no support for shared projects in .Net Core.

Author: Gimly

src/FluentAssertions.AspNetCore.Mvc/project.json

@@ -1,6 +1,14 @@
 {
   "version": "1.0.0-*",
 
+  "buildOptions": {
+    "compile": {
+      "include": [
+        "..\\FluentAssertions.Mvc.Shared\\**\\*.cs"
+      ]
+    }
+  },
+
   "dependencies": {
     "NETStandard.Library": "1.6.0"
   },