Made multiline string literals ignore an initial newline.

frog/leg/scanner/string_scanner.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Scanner that reads from a String and creates tokens that points to
  * substrings.
  */
 class StringScanner extends ArrayBasedScanner<SourceString> {
   final String string;
@@ skipping 44 matching lines @@
 
   String get stringValue() => toString();
 
   Iterator<int> iterator() =>
       new StringCodeIterator.substring(internalString, begin, end);
 
   SourceString copyWithoutQuotes(int initial, int terminal) {
     assert(0 <= initial);
     assert(0 <= terminal);
     assert(initial + terminal <= internalString.length);
-    assert((internalString.substring(begin, begin + initial) ==
-                ["", "'", "@'", "'''", "@'''"][initial]) ||
-           (internalString.substring(begin, begin + initial) ==
-                ['', '"', '@"', '"""', '@"""'][initial]));
-    assert((internalString.substring(end - terminal, end) ==
-                ["", "'", null, "'''"][terminal]) ||
-           (internalString.substring(end - terminal, end) ==
-                ['', '"', null, '"""'][terminal]));
-
     return new SubstringWrapper(internalString,
                                 begin + initial, end - terminal);
   }
 
   bool isEmpty() => begin == end;
 }