handle Delivery Receipt(deliver_sm) Format

[komuw]

The informational content of an SMSC Delivery Receipt may be inserted into the
short_message parameter of the deliver_sm operation. The format for this Delivery Receipt
message is SMSC vendor specific but following is a typical example of Delivery Receipt report:

id:IIIIIIIIII sub:SSS dlvrd:DDD submit date:YYMMDDhhmm done
date:YYMMDDhhmm stat:DDDDDDD err:E Text: . . . . . . . . .

see: Appendix B Delivery Receipt Format of SMPP spec v3.4 document

[komuw]

This is going to be hard to do and I'm not sure it is worth the effort.

The delivery receipt format is vendor specific; each SMSC/telco can have their own.
The way other smpp clients implement this is via hand-wavy regex. I'm not convinced this is worthy of tackling.

see:

1. Vendor specific delivery receipt format breaks Deliver_sm opentelecoms-org/jsmpp#62
2. SMPP raises error when trying to parse Safaricom delivery reports. praekeltfoundation/vumi#298 (<- Safaricom)
3. The SMPP transport should look for PDU params to detect delivery reports praekeltfoundation/vumi#637

[komuw]

One way to do this is to let users who know their SMSC's specific delivery receipt format to write a python regex for it; and then they can pass that regex in when they are instantiating a naz client. naz would then try and use that regex in a try ... except.. pass block.

But it is still a bad idea.