Removed the exec(String...) method in KotlinCompiler

It's important to be aware of what stream the messages will be written to, so such a default implementation is harmful

compiler/cli/src/org/jetbrains/jet/cli/KotlinCompiler.java

@@ -72,7 +72,7 @@ public class KotlinCompiler {
      */
     public static void doMain(KotlinCompiler compiler, String[] args) {
         try {
-            ExitCode rc = compiler.exec(args);
+            ExitCode rc = compiler.exec(System.out, args);
             if (rc != OK) {
                 System.err.println("exec() finished with " + rc + " return code");
                 System.exit(rc.getCode());
@@ -83,10 +83,6 @@ public class KotlinCompiler {
         }
     }
 
-    public ExitCode exec(String... args) {
-        return exec(System.out, args);
-    }
-
     public ExitCode exec(PrintStream errStream, String... args) {
         CompilerArguments arguments = createArguments();
         if (!parseArguments(errStream, arguments, args)) {