Updated CHANGELOG

CHANGELOG

@@ -1,3 +1,33 @@
+0.5 (2010-05-10)
+----------------
+
+Big Changes:
+
+* Syntax change: Use labeled expressions and variables instead of $1, $2, etc.
+* Syntax change: Replaced ":" after a rule name with "=".
+* Syntax change: Allow trailing semicolon (";") for rules
+* Semantic change: Start rule of the grammar is now implicitly its first rule.
+* Implemented semantic predicates.
+* Implemented initializers.
+* Removed ability to change the start rule when generating the parser.
+* Added several compiler optimizations -- 0.5 is ~11% faster than 0.4 in the
+  benchmark on V8.
+
+Small Changes:
+
+* PEG.buildParser now accepts grammars only in string format.
+* Added "Generated by ..." message to the generated parsers.
+* Formatted all grammars more consistently and transparently.
+* Added notes about ECMA-262, 5th ed. compatibility to the JSON example grammar.
+* Guarded against redefinition of |undefined|.
+* Made bin/pegjs work when called via a symlink (issue #1).
+* Fixed bug causing incorrect error messages (issue #2).
+* Fixed error message for invalid character range.
+* Fixed string literal parsing in the JavaScript grammar.
+* Generated code improvements and fixes.
+* Internal code improvements and fixes.
+* Improved README.md.
+
 0.4 (2010-04-17)
 ----------------