Issue 29 Network State

This pull request addresses issue #29 Provide the Current Network State. 

Just adds two methods into Merlin class which will retrieve the network info from a given context and return the network status. 

~~I was tempted to create a dummy Application in the android manifest and have it static so that you would not be required to pass a context in order to retrieve a network status, but there wouldn't be any guarantee that the onCreate would be called before someone tried to access the isConnected method.~~

^^ Me forgetting that this is a library :tongue: 


> therefore `available` means a network is connection but potentially you have not got an actual internet connection