talkatu/talkatu

ebabd7682683
Update TalkatuMessage:id to be a string.

Many modern protocols are using uuids as id's and forcing that into a uint64 is
going to lead to collisions. So instead just use a string which should work for
everything.

Testing Done:
Ran the demo and unit tests.

Reviewed at https://reviews.imfreedom.org/r/879/
# Building
Talkatu uses [meson](https://mesonbuild.com) as it's build system.
Meson requires you to build in a directory other than the source directory.
To compile you can use the following commands:
```
meson build
cd build
ninja install
```