Website fixes

So many things, i can't even ...

DONE
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[*] API: do not UPCASE code in headers
[*] Anchor: stopped looking nice on h2/h3's, needs to look nice on h1/h2/h3/h4/h5's
[*] Blog: sidebar headers should link to tag pages
[*] tag pages bro
[*] upgrade middleman
[*] fix upgrade bugs
[*] API: tabs need .active/:hover styling
[*] API: filters (peter has requests this back afew times)
[*] API: hide "tabs" if no content is present 
[*] API: Module github links are semi-random, see if we can fix or just remove them
[*] API: sidebar items longer then the available width, should be elipized.
[*] Sidebar: needs hover/active states
[*] API: Methods directory needs anchorability
[*] API: Properties directory needs anchorability
[*] API: Index directory needs anchorability
[*] API: 'Back to top' interferes with list content
[*] Sidebar: back-to-top parent is display-block
[*] Sidebar: right border doesn't fade away
[*] Header: Safari has strange hover state orange background:
[*] Sidebar: Headings seem blurry (regression)

and some many merged PR's

If someone can sanity check that would be lovely.