[base] add toString alias

Author: summer-alice

base/src/java/lang/String.d

@@ -20,6 +20,8 @@ version(Tango){
 alias TryImmutable!(char)[]  String;
 alias TryImmutable!(wchar)[] String16;
 
+alias toString = std.conv.to!string;
+
 String new_String( String cont, int offset, int len ){
     return _idup(cont[ offset .. offset+len ]);
 }

org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet6.d

@@ -55,6 +55,8 @@ import org.eclipse.swt.all;
 import org.eclipse.swt.layout.all;
 import org.eclipse.swt.widgets.all;
 
+import java.lang.String;
+
 void main(string[] args) {
     Display display = new Display();
     Shell shell = new Shell(display);