Update the srs crate to make it more useable as a full fledged srs client

[TheZoq2]

Hi. If you don't remember, I have a custom srs client https://gitlab.com/TheZoq2/srsrs which uses this projects srs crate to do most of the heavy listing.

This PR adds a few things which make that crate more useable:

• Support specifying a colaition. Defaults to Blue in all other crates as before
• Fix the name of the GameMessage lat_long field
• Fix an assertion that failed after a new update. I don't remember the meaning of those values, perhaps named constants should be used
• Add support for sending voice packets to the server

I think all crates will still build correctly, but I have some issues which are also present on master:

• datis-cmd fails with "Station does has no field named rpc"
• datis-core has 5 failed tests. Same tests as a fresh master
• doing cargo test in the root gives lua linker errors.

[rkusa]

I've fixed the tests on master and updated the repo to not require Lua during development. So forget about the env variables I've mentioned in my previous post, they are not required anymore. However, you have to run make test instead of cargo test now.

[TheZoq2]

Finally got around to taking care of this. I have pushed a new version. I also changed the way packet length is computed to be more readable as I was debugging issues with overlordbot interraction. Functionally. it should make no difference