pkg/third_party/html5lib: lots of cleanup

pkg/third_party/html5lib/lib/src/encoding_parser.dart

 library encoding_parser;
 
 import 'dart:collection';
 import 'constants.dart';
 import 'inputstream.dart';
-import 'utils.dart';
 
 // TODO(jmesserly): I converted StopIteration to StateError("No more elements").
 // Seems strange to throw this from outside of an iterator though.
 /**
  * String-like object with an associated position and various extra methods
  * If the position is ever greater than the string length then an exception is
  * raised.
  */
 class EncodingBytes extends IterableBase<String> {
   final String _bytes;
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     }
   }
 }
 
 
 bool isSpaceOrAngleBracket(String char) {
   return char == ">" || char == "<" || isWhitespace(char);
 }
 
 typedef bool CharPreciate(String char);