Hardening compiler to accept empty CompilerOptions object

src/compiler/commandLineParser.ts

@@ -157,11 +157,7 @@ module ts {
     ];
     
     export function parseCommandLine(commandLine: string[]): ParsedCommandLine {
-        // Set default compiler option values
-        var options: CompilerOptions = {
-            target: ScriptTarget.ES3,
-            module: ModuleKind.None
-        };
+        var options: CompilerOptions = {};
         var filenames: string[] = [];
         var errors: Diagnostic[] = [];
         var shortOptionNames: Map<string> = {};