update the code examples to stress the importance of parameter 'escape=...'

First of all thanks a lot for this very nice piece of code!

What steps will reproduce the problem?
1. set up your Xbees in API mode, with the API mode = 2 (AP = 2, means it 
escapes some special bits)
2. run the exemple code that is on http://code.google.com/p/python-xbee/
3. does not work (no frame response displayed , even if you can see in any 
terminal that your Xbee is fine ...)

What is the expected output? What do you see instead?
My point is simply that is is easy for a dummy newbie (like me!) to spend hours 
in trying debugging, while it is a simple parameters issue. I know it is in the 
documentation (thanks for this too ;-)) but it is so important that it should 
be added, I think, as a comment in the exemple code (e.g. #use Zigbee instead 
of Xbee if you are using Series 2 AND add "escape = True" to parameters if 
their AP parameter is set to 2.

What version of the product are you using? On what operating system?
2.1 on a Mac (Python 2.7) but it does not matter.

Please provide any additional information below.
Thank you again and Best Regards

Original issue reported on code.google.com by bertdelo...@gmail.com on 24 Apr 2013 at 10:39

flyte / python-xbee

update the code examples to stress the importance of parameter 'escape=...' #39