added logic to provide active class to active about menu page
removed empty categories strings from all posts & pages
added tags to bottom of blog post teasers
created blog index page, containing posts by category. Updated links in tag cloud and blog post teaser references.
completed blog index, providing posts by date and tag. id's provided so links from tags and dates on other blog pages are directed to the appropriate spot in the blog index page. Also created posts-by-date-min include to provide on the blog posts page. Added new layout - blog-index - providing two half-page columns