Enhancement: Allow creation of custom beacon templates

[russdill]

Beacon Simulator currently supports a set of known beacon formats. There are a number of companies creating there own beacons with proprietary formats. It'd be really useful to properly scan them and transmit them as well.

altbeacon provides support for custom layouts via the 'setBeaconLayout' call:

https://altbeacon.github.io/android-beacon-library/javadoc/org/altbeacon/beacon/BeaconParser.html#setBeaconLayout-java.lang.String-

It'd be really useful to have the ability to add custom templates based on this call.