Remove java script resources that are 404ing.

Remove static java script tags for bootstrap.min and docs.min which were
throwing 404 messages.  These were copied from the Bootstrap template
and are not needed because we are including all java scripts earlier in
the template with javascript_include_tag 'application'.
Improve redirection after blog post delete.

Improve redirection after blog post delete by sending the user back to
the referrer unless the referrer is the blog post which was just
deleted.  In that case send the user to the root path, since sending
them back to where they came from is now impossible.
Dynamically generate archive links.

Dynamically generate archive links using some Time class gymnastics in
the application layout.
Add archive function to BlogPost class.

Add archive function to BlogPost class to retrieve a listing of blog
posts for a given month.  Can be used to display a grouping of
archived blog posts for the requester.  Takes a string with concatenated
year and month as input like 201406.