Removed the 'needsstorage' thing from Dsymbol. Arguments are not always given storage when applicable. This is not longer treat specially

in this regard. Code for accessing nested variables and contexts rewritten. Probably more. Fairly well tested.

tests/mini/nested6a.d

@@ -12,28 +12,31 @@ void main()
         int j;
         void func()
         {
-	    int k;
+            int k;
             printf("C.func() %d\n", i++);
 
             class C2
             {
-	        int l;
+                int l;
                 void func2()
                 {
+                    printf("in C2.func2()\n");
                     printf("C2.func2() %d\n", i++);
                 }
-		int m;
+                int m;
             }
 
             {
-                scope c2 = new C2;
+                printf("new C2\n");
+                auto c2 = new C2;
+                printf("C2.func2()\n");
                 c2.func2();
             }
-	    int n;
+        int n;
         }
-	int o;
+    int o;
     }
 
-    scope c = new C;
+    auto c = new C;
     c.func();
 }