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.
Show dismiss posts/topics buttons on category filtered lists
FIX: Make shortcut 'c' global for creating a topic

https://meta.discourse.org/t/keyboard-shortcut-c-create-a-new-topic-does-not-work-globally/18975
Apply comments from eviltrout, using this.get('category.id'), and use snake case for category_id
Call open directly to avoid deprecation warning
BUG: phpBB lists not properly converted

bbcode-to-md happily ignores all phpBB's lists. The list syntax is
    [list][*]item 1
    [*]item 2
    [/list]
and 
    [list=1][*]item 1
    [*]item 2
    [/list]
respectively for [ul] and [ol]s. Luckily, phpBB adds closing tags for [*] items. My workaround simply converts phpBBs lists into bbcode using [ul] and [ol] which then can be converted by the standard bbcode-to-md code.
Use a site setting for maximum summary results
one more spot where code can be reused
PERF: move excerpt to raw, expose i18n to handlebars
PERF: reduce one view, cleaner pattern for component visibility
PERF: don't render dropdowns till we need them
PERF: don't render the category list if we are not showing it.