Merge pull request #1 from tomcatter/master

修改
fix empty fn
add interface
add varible to config access_id and access_key
添加安装方法
fix service name, add custom push receiver
Merge branch 'master' of https://github.com/gengen1988/XGPush
fix classname
第二次修改
Merge remote-tracking branch 'upstream/master'

Conflicts:
	www/xgpush.js