Reading binary messages

[David Ford]

MMS notification is sent as a URL via SMS.

bluesms.py has initial support for MMS however my phone has been out for
buzzfix for a while.  with a growing number of phones and carriers,
you're only allowed to fetch that URL from the phone number it's
designated for.  further, it's normal to require you to fetch via your
APN proxy.  do note that the PDU decoding for these binary messages is
broken in FSO and needs to be fixed.  i'll work on that when i get my
phone back next week.  that means that the URL sent to you could have
junk prefixed to the URL, or the front of the URL could be chopped off.

step 1: MMSC sends you an SMS with a URL
step 2: your phone should bring up GPRS if not already up
step 3: your phone should fetch the MMS by way of your APN proxy using
the given URL.
step 4: decode the MMS as applicable
step 5: save the content you decoded and notify the message reader
program that it's ready for rendering
step 6: shut down GPRS if necessary

-david