Update target spec to the latest version
Adjusted HTML output for fenced code to add language class to `core` rather than `pre`

This mirrors the following commit: https://github.com/jgm/stmd/commit/f5a456175cfde7bad10fad96e9fa17d357c8244a
Added anchors to linkDestination and main regexes

This mirrors the following commits:
  - https://github.com/jgm/stmd/commit/1f43f5936bb856d317686641a46388030acd8566
  - https://github.com/jgm/stmd/commit/7d4b88b7a78320f95345c22aba2776fe68b6cd1f
Don't treat "br" as block-level; add "iframe" as block-level

This mirrors the following commits:
  - https://github.com/jgm/stmd/commit/7274556fb19a2da10ae8a0644c2710c191ab85b1
  - https://github.com/jgm/stmd/commit/1325976ea8a23d8a7939486b44ace20f41b9635a
Fix incorrect handling of nested emphasis

This mirrors the following commits:
  - https://github.com/jgm/stmd/commit/76e133cafe0f45e44c57e391c67af1c2f0057004
  - https://github.com/jgm/stmd/commit/3c89f2660280266d9d82cf398b2ff9ba5d693fff
  - https://github.com/jgm/stmd/commit/2cf0750a7a507eded4cf3c9a48fd1f924d0ce538

Issue originally reported here: https://github.com/jgm/stmd/issues/48
Add recent updates to changelog
Prepare for 0.1.1 release
Merge pull request #1 from colinodell/sync-with-spec

Sync with changes to latest spec