Added Google's easypermission

[XinyueZ]

I import easypermission which is a compat-solution about permission-check on device up from M. With this library the app can tell user to set permission in system-setting under app-category directly.

Try this branch and evaluate wheather to be merge onto master. Instead by easypermission I've removed form package associated with permssion in source.

[hefuyicoder]

Thanks your code , it works well.