Add notification.mp3

Support audio notifications in Internet Explorer too
Merge pull request #1106 from garysharp/notification-mp3

Add notification.mp3 to support IE
Change room caching to make it timeout really quickly.  Mitigates #1047 as all caches reflect the truth after ~1s.
Merge pull request #1117 from JabbR/mitigate-room-cache

Mitigate issues with room cache and scaleout
Added marked.js as a submodule
Converted from PageDown to marked.js
Enabled markdown for content
Added syntax highlighting with highlight.js
Changed from submodule to nuget package
Removed unused CSS which interfered with syntax highlighting
Merge pull request #1125 from khellang/markdown-subset-support

Markdown subset support
#1123 Create owners command.
Add creator to list owners command.  Create user tagging method (which can be used by other components in the future).  Switch to dynamically generating the list of resources that get sent to the client.
Catch everything on the bg thread
Fix notifications page's 404, #1131
Merge pull request #1132 from JabbR/fix-notifications

Fix notifications page's 404, #1131
Fix issue where GitHub issue applies our CSS. Fixes #1134
Forgot to enable GFM

This doesn't change the inline stuff much, but it should enable ~~del~~ elements.
Merge pull request #1137 from khellang/patch-1

Forgot to enable GFM
#1123 Create owners command.