allow multiple manufacturer specific data

[luisfelrib]

this PR adds support for multiple manufacturer specific data.

The current behaviour if the advertisement has multiple manufacturer specific data is always rewrite with the last one.

This is not desirable in our situation. We have seen beacons with multiple manufacturer specific data.

This PR changes the interface for the manufacturer specific data for it to be a list of objects instead of just the last object. The list of objects contais all the manufacturer specific data.

An example of payload with multiple manufacturer specific data we captured is:

4024689e190491e00201061aff4c000215e2c56db5dffb48d2b060d0f5a71096e000000001c5020a00041653514307ff000000540000

[jeffyactive]

Thanks for the PR @luisfelrib. We've never encountered a device that sends multiple manufacturer specific data in a single packet, would be curious to know more about that device so we can add to Sniffypedia and make an example in the web version of advlib.

The example you've provided, however, does not seem to represent a valid BLE packet as it is over 37 bytes. We propose that we clarify the multiple manufacturer specific data case first and then update the code in consequence. Please advise on the above, thanks!