Rename css -> style

Was bothering me for a while
Add post indices to inline posts

Best for backlinks, probably want to remove for regular inlines.
Fix hakase.styl whitespace

tabs -> spaces, remove trailing whitespace.

Like, technically, tabs are still superior, but:

1. github defaults to 8 spaces with real tabs, which is bothersome
2. html <pre> does as well
3. lisp-style indentation requires a mix of tabs and spaces until
   elastic tabs become standard.
4. my vimrc shows real tabs in ugly visible characters, which has
   trained me to react badly to them.

Perhaps someday, tabs will get their comeuppance...
Hide original backlink in favor of idx

Very clean looking, except for the probably too-large indentation.

Code is really ugly though. Needs a rethink, somehow.
Merge branch 'compact-threading'
Fix edge case in youtube linker

www.youtu.be why.jpg