* Wireless: Optimize memory usage in StreamMessageQueue (use an array of string ropes, that we only concatenate once). Allowed to relax the throttling, making transfers that much faster.
* Persist: Add a "zstd" codec, that uses the "luajit" codec, but compressed via zstd. Since both of those are very fast, it pretty much trounces everything in terms of speed and size ;).
* Persist: Implemented a "writes_to_file" framework, much like the existing "reads_from_file" one. And use it in the zstd codec to avoid useless temporary string interning.
* Metadata: Switch to the zstd codec.
There have been a couple of these this month, and keeping stuff that should only ever run once piling up in their respective module was getting ugly, especially when it's usually simple stuff (settings, files).
So, move everything to a dedicated module, run by reader.lua on startup, and that will actually only do things once, when necessary.
