Adding ability to set a stream in the template library.

When setting a stream in the template library, basically you are
telling Pyro to use the stream parser to process the view. The stream
parser goes in and modifies tags to make things like multiple relations
work (ie, tags with parameters). To see a working exampl, see the blog
module.
Adding stream parse support to the blog

This sets up the blog to use our special streams parse function to
parse blog content, allowing tags with parameters.
Fixing issue with passing rows in streams parse

Passing the row_id as `row_id=id` was causing problems when it was
inside of a variable loop. Changing it to `row_id="{{ id }}"` helps,
however, we now have to deal with variable naming collisions for
overriden stream variables that are not inside tag loops. This is a Lex
issue, however, so it should be fixed in Lex.
Stopping the cellspacing="0" madness