Changed youtube regex to match id-s in more links

Found in [this answer](http://stackoverflow.com/questions/8388223/youtube-url-id-regex).

[Tested here](http://www.phpliveregex.com/p/30A).
Merge pull request #14 from SoonDead/patch-1

Changed youtube regex to match id-s in more links
Update post layout (more to come)
Fix controls on short posts.
Revert global box-sizing change
Again with the short posts
Don't use min-height on small screens