[csharp] able to compile with dotnet cli under Linux

1, moved xproj file into Antlr4.Runtime sub-folder to keep convention
2, removed two cs files that no longer needed
3, fill in missing using directives

runtime/CSharp/runtime/CSharp/Antlr4.DotNetCore.sln

@@ -3,7 +3,7 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 14
 VisualStudioVersion = 14.0.25420.1
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Antlr4.Runtime.DotNetCore", "Antlr4.Runtime.DotNetCore.xproj", "{12962409-846E-4B80-933A-BC484D264132}"
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Antlr4.Runtime.DotNetCore", "Antlr4.Runtime\Antlr4.Runtime.DotNetCore.xproj", "{12962409-846E-4B80-933A-BC484D264132}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Atn/OrderedATNConfigSet.cs

@@ -1,42 +0,0 @@
-/* Copyright (c) 2012-2016 The ANTLR Project. All rights reserved.
- * Use of this file is governed by the BSD 3-clause license that
- * can be found in the LICENSE.txt file in the project root.
- */
-using Antlr4.Runtime.Atn;
-using Antlr4.Runtime.Sharpen;
-
-namespace Antlr4.Runtime.Atn
-{
-    /// <author>Sam Harwell</author>
-    public class OrderedATNConfigSet : ATNConfigSet
-    {
-        public OrderedATNConfigSet()
-        {
-        }
-
-        public OrderedATNConfigSet(ATNConfigSet set, bool @readonly)
-            : base(set, @readonly)
-        {
-        }
-
-        public override ATNConfigSet Clone(bool @readonly)
-        {
-            Antlr4.Runtime.Atn.OrderedATNConfigSet copy = new Antlr4.Runtime.Atn.OrderedATNConfigSet(this, @readonly);
-            if (!@readonly && this.IsReadOnly)
-            {
-                copy.AddAll(this);
-            }
-            return copy;
-        }
-
-        protected internal override long GetKey(ATNConfig e)
-        {
-            return e.GetHashCode();
-        }
-
-        protected internal override bool CanMerge(ATNConfig left, long leftKey, ATNConfig right)
-        {
-            return left.Equals(right);
-        }
-    }
-}

runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Dfa/SparseEdgeMap.cs

@@ -4,6 +4,7 @@
  */
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using Antlr4.Runtime.Sharpen;
 
 namespace Antlr4.Runtime.Dfa

runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Misc/DoubleKeyMap.cs

@@ -1,58 +0,0 @@
-using System;
-using System.Collections.Generic;
-
-namespace Antlr4.Runtime.Misc
-{
-	public class DoubleKeyMap<K1, K2, V>
-	{
-		Dictionary<K1, Dictionary<K2, V>> data = new Dictionary<K1, Dictionary<K2, V>>();
-
-		public V put(K1 k1, K2 k2, V v)
-		{
-			Dictionary<K2, V> data2 = data.get(k1);
-			V prev = null;
-			if (data2 == null)
-			{
-				data2 = new Dict<K2, V>();
-				data.put(k1, data2);
-			}
-			else {
-				prev = data2.get(k2);
-			}
-			data2.put(k2, v);
-			return prev;
-		}
-
-		public V get(K1 k1, K2 k2)
-		{
-			Dictionary<K2, V> data2 = data.get(k1);
-			if (data2 == null) return null;
-			return data2.get(k2);
-		}
-
-		public Dictionary<K2, V> get(K1 k1) { return data.get(k1); }
-
-		/** Get all values associated with primary key */
-		public ICollection<V> values(K1 k1)
-		{
-			Dictionary<K2, V> data2 = data.get(k1);
-			if (data2 == null) return null;
-			return data2.values();
-		}
-
-		/** get all primary keys */
-		public HashSet<K1> keySet()
-		{
-			return data.keySet();
-		}
-
-		/** get all secondary keys associated with a primary key */
-		public HashSet<K2> keySet(K1 k1)
-		{
-			Dictionary<K2, V> data2 = data.get(k1);
-			if (data2 == null) return null;
-			return data2.keySet();
-		}
-	}
-
-}

runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Misc/MultiMap.cs

@@ -2,6 +2,7 @@
  * Use of this file is governed by the BSD 3-clause license that
  * can be found in the LICENSE.txt file in the project root.
  */
+using System;
 using System.Collections.Generic;
 using Antlr4.Runtime.Sharpen;
 

runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Misc/RuleDependencyChecker.cs

@@ -354,7 +354,7 @@ namespace Antlr4.Runtime.Misc
                 }
                 foreach (Transition transition in state.transitions)
                 {
-                    if (transition.TransitionType != TransitionType.Rule)
+                    if (transition.TransitionType != TransitionType.RULE)
                     {
                         continue;
                     }
@@ -459,7 +459,7 @@ namespace Antlr4.Runtime.Misc
         {
         }
 
-#if PORTABLE
+#if PORTABLE || DOTNETCORE
         public interface ICustomAttributeProvider
         {
             object[] GetCustomAttributes(Type attributeType, bool inherit);

runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Tree/ParseTreeProperty.cs

@@ -2,7 +2,11 @@
  * Use of this file is governed by the BSD 3-clause license that
  * can be found in the LICENSE.txt file in the project root.
  */
+#if NET40PLUS
+using System.Collections.Concurrent;
+#else
 using Antlr4.Runtime.Sharpen;
+#endif
 
 namespace Antlr4.Runtime.Tree
 {

runtime/CSharp/runtime/CSharp/project.json

@@ -1,16 +1,23 @@
 {
-  "buildOptions": {
-    "define": [ "DEBUG", "TRACE", "DOTNETCORE", "NET40PLUS", "NET45PLUS" ],
-    "keyFile": "../Antlr4.snk",
-    "xmlDoc": true
-  },
-  "dependencies": {
-    "NETStandard.Library": "1.6.0"
-  },
+  "version": "4.5.3-*",
   "frameworks": {
-    "netstandard1.5": {
-      "imports": "dnxcore50"
+    "netstandard1.3": {
+      "dependencies": {
+        "NETStandard.Library": "1.6.1"
+      }
     }
   },
-  "version": "4.5.3-*"
-}
+  "dependencies": {},
+  "buildOptions": {
+    "xmlDoc": true,
+    "keyFile": "../Antlr4.snk",
+    "define": [
+      "DOTNETCORE",
+      "NET40PLUS",
+      "NET45PLUS"
+    ],
+    "nowarn": [
+      "CS1591"
+    ]
+  }
+}