bolus command

discovered bolus command using this script:

https://gist.github.com/bewest/186e800d687b3b4fb469

Here's the new tool:

```
$ ./bin/mm-bolus.py -h
usage: mm-bolus.py [-h] [--serial SERIAL] [--port PORT] [--no-op]
                   [--skip-prelude] [--no-rf-prelude] [--skip-postlude] [-v]
                   [--init] [--units STROKES]

mm-bolus.py - Send bolus command to a pump.

optional arguments:
  -h, --help       show this help message and exit
  --serial SERIAL  serial number of pump [default: 208850]
  --port PORT      Path to device [default: ]
  --no-op          Dry run, don't do main function
  --skip-prelude   Don't do the normal prelude.
  --no-rf-prelude  Do the prelude, but don't query the pump.
  --skip-postlude  Don't do the normal postlude.
  -v, --verbose    Verbosity
  --init           Send power ctrl to initialize RF session.
  --units STROKES  Amount of insulin to bolus. [default: None)]

XXX: Be careful please. Units might be wrong. Keep disconnected from pump
until you trust it by observing the right amount first.
bewest@patient:~/src/decoding-carelink$ 


```
This was tested on a MM515.