Version bump to 2.0.2.

Minor version bump to 2.0.2 after some minor changes to the demo
template files blog-side-bar.inc and blog-post.php
Foolproof comments output in demo files.

Minor changes to foolproof the outputting of comments only if comments
feature is installed. Helps to avoid conflict with post-install custom
use of comment templates and fields with similar names to Blog's.