* add badges to default branch
* add instructions in readme for post badges
* update readme
* add instructions for badges to readme yaml
* switch GH badges to iframes and remove comment out cran badges
* remove cran comment and update yaml table in readme file.
* Update README.md
* Update main.css
Tags will display as plain text if a user adds tags to a post. If user
sets 'link-tags: true' in _config.yml, then Jekyll will make a new page
for each tag which lists all posts with given tag (provided the site is
not deployed through GitHub pages)
