tests: import unittest via package: url

tests/html/websql_test.dart

 library WebDBTest;
 import 'dart:async';
 import 'dart:html';
 import 'dart:web_sql';
-import '../../pkg/unittest/lib/unittest.dart';
-import '../../pkg/unittest/lib/html_individual_config.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_individual_config.dart';
 
 void fail(message) {
   guardAsync(() {
       expect(false, isTrue, reason: message);
     });
 }
 
 Future<SqlTransaction> transaction(SqlDatabase db) {
   final completer = new Completer<SqlTransaction>.sync();
 
@@ skipping 121 matching lines @@
         var row = resultSet.rows.item(0);
         expect(row.containsKey(columnName), isTrue);
         expect(row[columnName], 'Some text data');
         expect(resultSet.rows[0], row);
       }).then((_) {
         return dropTable(tx, tableName);
       });
     });
   });
 }