Revert "Target .NET Core App and fix React.Core reference"

This reverts commit 8df5eaa.

Author: chriscamplejohn

tutorial-code/project.json

@@ -16,7 +16,7 @@
     "Microsoft.Extensions.Logging.Debug": "1.0.0",
     "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
     "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
-    "React.AspNet": "3.0.0"
+    "React.AspNet": "3.0.0-rc1"
   },
 
   "tools": {
@@ -25,15 +25,7 @@
   },
 
   "frameworks": {
-      "netcoreapp1.0": {
-        "dependencies": {
-          "Microsoft.NETCore.App": {
-            "type": "platform",
-            "version": "1.0.0"
-          }
-        }
-    },
-    "net46": {}
+    "net46": { }
   },
 
   "buildOptions": {