1. Removed lots of duplication
2. Added warnings and fixed some dim regex
3. New: set a start line number for any code snippet
4. New: set a start, end, or range for include_code
5. New: added option to disable line numbers linenos:false
Fixes#478#484
2. Refactored Octopress filters into Liquid filters and pre/post render filters (using post_filters plugin)
3. Added methods to raw plugin to prevent Markdown and Textile from parsing blocks
4. Updated render partial to invoke the pre_render method of post_filters
5. Moved Rubypants filter out of default.html into Octopress post_render filters
6. Added raw's safe_wrapper method to codeblock and include_code filters
