fix #1593 - also honour allowNonTsExtensions flag when there is no extension

Author: jrieken

src/compiler/parser.ts

@@ -5231,7 +5231,7 @@ module ts {
                 }
             }
             else {
-                if (!(findSourceFile(filename + ".ts", isDefaultLib, refFile, refPos, refEnd) || findSourceFile(filename + ".d.ts", isDefaultLib, refFile, refPos, refEnd))) {
+                if (!((options.allowNonTsExtensions && findSourceFile(filename, isDefaultLib, refFile, refPos, refEnd)) || findSourceFile(filename + ".ts", isDefaultLib, refFile, refPos, refEnd) || findSourceFile(filename + ".d.ts", isDefaultLib, refFile, refPos, refEnd))) {
                     diagnostic = Diagnostics.File_0_not_found;
                     filename += ".ts";
                 }