Include first example post and ditch handlebars for swig

Lots of changes since it's still early on. Basically handlebars was
nice, but didn't really have the inheritence I wanted so I ditched it
for swig.

Example posts are now generated and I think I'll try a structure as
illustrated by example-post where it's id#slug and then there's a
template and some metadata for the post in the directory. Really id and
slug are also metadata, but keeping id at the directory level makes it
hopefully less likely that I screw up and duplicate ids (since I'll
probably be doing posts by hand for a while). Keeping the slug at the
directory level just helps me find posts.

Also added a gulp clean. To prevent the static assets from disappearing
forever when cleaned, I also added a static folder and assets will get
copied out of it.