Implement Bluetooth functionality

[Nandez500]

After our simple app setup (#2), one of our next steps is to implement Bluetooth connectivity to connect to our Pi. This issue is co-dependent on #5.

Helpful link: https://developer.android.com/guide/topics/connectivity/bluetooth.html

[Nandez500]

@Lightning750

I have done a couple of things to this branch:

1. Updated it with the master branch. It now has all the code and activities I wrote, the bluetooth activity can be accessed by pressing "connect bluetooth" on the main menu.
2. Added a "RecyclerView" to the bluetooth activity. This is the new version of "ListView" for android.

Try this guide to display the arrayList of bluetooth devices in the recyclerView. It involves creating an "adapter" class that takes your arrayList and displays it in the
https://stackoverflow.com/questions/37786796/how-to-display-an-arraylist-in-a-recyclerview