Split layouts into includes

Also standardise on date for published at. Ruhoh (if I recall) borked on
date parsing, so I needed to include redundant data in each post's meta
data to hold the month name and all that crap. That's gone in this
change.

The url format has changed to /blog/:title. I might reintroduce the date
there, even though these urls are supposed to be perma. Oh well.
Move all of the India posts to their own folder

Jekyll bases categories on the location of a _posts directory (there can
be multiple). So this change moves the India travel posts into their own
directory to auto categorise them.

I'm pretty sure they all include the India category in their meta data
as well, but they're such a distinct part of the website (having being
imported from the old php site) that they can go on their own.
Add sidebar links to me on external sites

The Skype link has an alert, I should probably change that. To what
though? Some nifty hover box?  ¯\_(ツ)_/¯

Ideally, the links would be built programmatically but there doesn't
seem to be a nice and safe way to do that. Hmm.
Increase icon sizes
Make sidebar icons black and horizontally spaced
Change url permalink format
Add information to the side bar
Remove reference to sablog

The South America blog has been rolled up into this one, so we don't
need to refer as a separate thing any more