Auto-anchor attribute regexes, document _validTags
FIX: Use lang- prefixes for HLJS; add nohighlight for ...

text; use a proper whiteListTag() call.

Old posts are not affected - no global rebake is necessary.
Clean up validateAttribute() function

Remove code duplication
FEATURE: Allow explicit rel="nofollow" on links
Fix JSHint
Fix data-* behavior (failure to understand own docs)
Update Markdown tests
Add emoji pl_PL localization
Remove href attribute from tab link to prevent duplicate event on enter.

Because Discourse doesn't preventDefault on links with an href of "#"
this tab-able link was firing a click event when enter was pressed. This
had the unfortunate side effect of breaking the history, making routing
and navigation unreliable.
Add additional fields that indicate reply

When scanning for where a reply starts, three lines in a row matching common email reply headers indicate the start of a reply. Add 'Cc', 'Bcc', and 'Date' because these are also common.
css tweak - expanding some room for zh_CN
FIX: Don't include reverts in release notes
FIX: Include security in release notes
FIX: Strip the word "SECURITY" from the output too
minor style tweaks to file upload modal
some possible improvements to build times

- use our new infrastructure based on LXC and EC2
- enable caching for bundler
- use schema:load (best practice)
- use --deployment (best practice when a Gemfile.lock is around)
make the env vars global
looks like db:migrate is required
Merge pull request #2951 from joshk/patch-1

some possible improvements to build times
faster and more stable bundle installing