check to find if internet is reachable

[ghost]

I added a simple decorator as well as checking for internet connection with ping to see if whether the host is down or internet is not reachable. Optionally, @retry keyword argument can be used to retry to reach internet in case it fails and @opt_exception to raise an optional exception to check for it somewhere else.

[drasko]

@mitghi this pull req is wrong... You are trying to merge next onto the master :).

Please fork the next branch, post a pull request onto the next.

I am sorry for the confusion, but after v1.1 we will ditch the next and keep only master. It will be easier :).

Thanks!

[ghost]

@drasko oh sorry, i see. I correct it. Thanks