Restructure pkg/unittest and pkg/webdriver to follow the pub conventions.

tests/html/svg_3_test.dart

-#library('SVG3Test');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
+library SVG3Test;
+import '../../pkg/unittest/lib/unittest.dart';
+import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:html';
 
 // Test that SVG elements have the operations advertised through all the IDL
 // interfaces.  This is a 'duck typing' test, and does not explicitly use 'is'
 // checks on the expected interfaces (that is in SVGTest2).
 
 main() {
 
   var isString = predicate((x) => x is String, 'is a String');
   var isStringList = predicate((x) => x is List<String>, 'is a List<String>');
   var isSVGMatrix = predicate((x) => x is SVGMatrix, 'is a SVGMatrix');
@@ skipping 119 matching lines @@
 
   testRect('rect_SVGTests', checkSVGTests);
   testRect('rect_SVGLangSpace', checkSVGLangSpace);
   testRect('rect_SVGExternalResourcesRequired',
            checkSVGExternalResourcesRequired);
   testRect('rect_SVGStylable', checkSVGStylable);
   testRect('rect_SVGLocatable', checkSVGLocatable);
   testRect('rect_SVGTransformable', checkSVGTransformable);
 
 }