Fix links to kaosfield (ka's homepage)

From http://kaosfield.net
To   http://www.kaosfield.net
Merge pull request #19 from devtokushima/fix-links-to-kaosfield

Fix links to kaosfield (ka's homepage)
Add a link to the slide for tokushima.rb 3
Merge pull request #20 from devtokushima/tokushimarb-3-slide

ほー。マージします。
Add a link to the slide for tokushima.rb 3
Fix GitHub pages URL scheme from https to http
Merge pull request #21 from devtokushima/fix-link-urls

Fix GitHub pages URL scheme from https to http