Markdown2

- [pull 524] Fix angles being escaped in style blocks (issue 523)
- [pull 527] Fix base64 images being corrupted in safe mode (issue 526)
- [pull 529] Add `breaks` extra with ability to hard break on backslashes (issue 525)
- [pull 532] Fix 493 persisting when `code-friendly` extra enabled
- [pull 535] Update `_slugify` to use utf-8 encoding (issue 534)
- [pull 536] Maintain order of appearance in footnotes
- [pull 538] Include HTML headers in TOC
- [pull 540] Add mechanism to prevent header ID counter resetting (issue 530)

- [pull 520] Allow more relative links in safe mode (issue 517)
- [pull 521] Always restore hashed HTML blocks (issue 185)
- [pull 522] Add `middle-word-em` extra

- [pull 500] Add `<thead>` tag to html-classes extra
- [pull 501] Fix link patterns extra matching against internal hashes
- [pull 502] Replace deprecated `optparse` with `argparse`
- [pull 506] Fix `_uniform_outdent` failing with empty strings (issue 505)
- [pull 509] Fix HTML elements not unhashing correctly (issue 508)
- [pull 511] Remove deprecated `imp` module (issue 510)
- [pull 512] Allow link patterns to be passed via extras dict
- [pull 513] Fix relative links not working in safe mode (issue 254)

- [pull 499] Fix images not being procesed correctly (498)

- [pull 483] Fix hashing nested HTML blocks
- [pull 486] Fix backslash being unable to escape raw HTML tags
- [pull 482] Add support for telegram spoiler in extras
- [pull 485] mermaid support
- [pull 487] Fix escaping ampersands in hrefs
- [pull 490] Fix indented codeblocks inside fences (489)
- [pull 490] Remove `code-color` extra

- [pull 477] Feature wavedrom support
- [pull 480] Fix mixing ordered and un-ordered lists combining into single list type