modified:   config.json
added /purchase and /donate to nav

	modified:   contents/connect/index.md
added twitter buttons

	new file:   contents/donate/index.md
	new file:   contents/donate/thanks.md
	new file:   contents/purchase/index.md
	new file:   contents/purchase/thanks.md

	modified:   templates/article.jade
	new file:   templates/flattr.html
	modified:   templates/layout.jade
	modified:   templates/nav.jade
added follow button
	new file:   templates/twitter-follow.html
	new file:   templates/twitter-mention.html
	new file:   templates/twitter-share.html