update readme
增加首字下沉mixin，增加example高亮，example改为使用css，因为旧IE不支持less.js
update readme
Merge branch 'master' of https://github.com/ecomfe/est into ecomfe-master

Conflicts:
	example/typography.html
Merge branch 'master' of https://github.com/ecomfe/est into ecomfe-master
update readme
Merge branch 'master' into gh-pages