Merge pull request #8 from lianqin7/master

设置align为空，就可以不使用js进行定位相关（交由css解决）
add test case for #8
 iframe-shim 1.0.2
update history
duplicate
duplicate
rebuild for class@1.1.0
update hist
fix Makefile
add maintainers
Merge branch 'master' of github.com:aralejs/overlay
update position to 1.0.1
update position to 1.0.1
update makefile
fixed #9
rebuild
update makefile travis
rebuild
fix position not correct when scrollbar show after render
simply code & add doc note