This is a big rewrite to use DBus calls directly instead of going
through go-bluetooth first.
This is a big change, but I believe it is an improvement. While the
go-bluetooth works for many cases, it's a layer in between that I
believe hurts more than it helps. Without it, we can just program
directly against the BlueZ D-Bus API. The end result is about 10% more
code.
With this rewrite, I fixed the following issues:
* All MapToStruct warnings are gone, like in
https://github.com/tinygo-org/bluetooth/issues/193.
* Advertisements can be restarted after they were stopped. Previously
this resulted in a panic.
* Looking at the source code of go-bluetooth, it appears that it
includes devices from a different Bluetooth adapter than the one
that's currently scanning. This is fixed with the rewrite.
* Fix a bug in Adapter.AddService where it would only allow adding a
single service. Multiple services can now be added.
This was actually the motivating bug that led me down to rewrite the
whole thing because I couldn't figure out where the bug was in
go-bluetooth (it's many layers deep).
* The `WriteEvent` callback in a characteristic now also gets the
'offset' parameter which wasn't provided by go-bluetooth.
This rewrite also avoids go-bluetooth specific workarounds like
https://github.com/tinygo-org/bluetooth/pull/74 and
https://github.com/tinygo-org/bluetooth/pull/121.
I have tested all examples in the smoketest-linux Makefile target. They
all still work with this rewrite.
