Merge pull request #1 from MozillaChina/master

merge
devtools.md translation from English to Chinese
appmanager.md and simulator md translation from English to Chinese
合并修改
Merge branch 'yuanwowo-master'
Merge pull request #16 from yuanwowo/master

Update devtools.md
Merge pull request #7 from MozillaChina/master

上游合并