append redcarpet for markdown rendering engine.
change theme to twitter original to show navigation bar. extract pages from index.md. fix some tiny problems.
Merge pull request #12 from agile459/theme

記事をHomeに表示するようにした。
add description in README.
add new of ipa event.
Merge pull request #13 from agile459/ipa

1/31のIPAイベントのお知らせを追加しました。
add logo image.
Merge pull request #14 from agile459/ipa

ロゴを追加した。
fix #15.
Merge pull request #16 from agile459/ipa

fix #15.
change logo image.
Merge pull request #17 from agile459/logo

change logo image.
add 2010-11-21-StartUp
add 2011-04-15-agilejapan2011
add 2012-03-16-agilejapan2012
add 2011-10-29-agilecasestudy01
add 2011-09-29-1029tuajairushiliyanjiuseminakaicui
add 2012-01-11-1117zhangzesanhuanyingmianqianghui
add 2012-04-05-agile459ajairusamuraidushuhuiinsongshan2kaicui
add 2012-07-21-20120728ajairusamuraidushuhui6kaicui