Rewrite of the connection setup.

I'd want to advice against using `use_connection()` more, as the
connection setup is less explicit, and also pollutes global memory.

Because, well:

    $ python -m this | head -n4 | tail -n1

;)

examples/run_example.py

@@ -1,10 +1,10 @@
 import os
 import time
-from rq import Queue, use_connection
+from rq import Queue, Connection
 from fib import slow_fib
 
-# Tell RQ what Redis connection to use
+
-use_connection()
+def main():
     # Range of Fibonacci numbers to compute
     fib_range = range(20, 34)
 
@@ -32,3 +32,9 @@ while not done:
         time.sleep(0.2)
 
     print 'Done'
+
+
+if __name__ == '__main__':
+    # Tell RQ what Redis connection to use
+    with Connection():
+        main()

examples/run_worker.py

@@ -1,8 +1,8 @@
-from rq import Queue, Worker, use_connection
+from rq import Queue, Worker, Connection
 
-# Tell rq what Redis connection to use
-use_connection()
 
 if __name__ == '__main__':
+    # Tell rq what Redis connection to use
+    with Connection():
         q = Queue()
         Worker(q).work()