Added post thumbnail to templates

Also added filter to surround thumbnail with container so we can
optionally crop the image via styles.
Added post thumbnail to templates

Also added filter to surround thumbnail with container so we can
optionally crop the image via styles.
Merge branch 'feature/featured-image-support' of https://github.com/realcrowd/_tk into feature/featured-image-support
Merge pull request #2 from realcrowd/feature/featured-image-support

Feature/featured image support