add release notes for version 0.4.0

notes/0.4.0.markdown

@@ -0,0 +1,14 @@
+
+This is a big update which adds template based site generation, batch processing
+and related features.
+
+* Template-based site generation
+* Support for tables of contents, autonumbering of documents and sections
+  and convenient cross-linking between documents for all supported markup
+  formats
+* Custom Directives (tags) for templates and text markup
+* Document Fragments that can be rendered separately from the main document content
+* New API for batch processing for parse, render and full transform operations
+* Parallel processing of parsers and renderers 
+* Completely restructured [manual](http://planet42.github.com/Laika/index.html)
+