Gatt helper error paths and cleanup

@matthewsibigtroth 

Add error paths and messages to BeaconConfigHelper and friends.
Collapse A->B->C methods.
Collapse A->B1->C1 and A->B2->C2 methods to A->B(1) and A->B(2) methods.
If the Beacon in config mode is too far away, ask the user to move it closer.
Add a sleep after the write which seems to make BLE more reliable (!)