* Persist: support serpent, and use by default over dump (as we assume consistency > readability in Persist).
* Logger/Dbg: Use serpent instead of dump to dump tables (it's slightly more compact, honors __tostring, and will tag tables with their ref, which can come in handy when debugging).
* Dbg: Don't duplicate Logger's log function, just use it directly.
* Fontlist/ConfigDialog: Use serpent for the debug dump.
* Call `os.setlocale(C, "numeric")` on startup instead of peppering it around dump calls. It's process-wide, so it didn't make much sense.
* Trapper: Use LuaJIT's serde facilities instead of dump. They're more reliable in the face of funky input, much faster, and in this case, the data never makes it to human eyes, so a human-readable format didn't gain us anything.
* Minor updates to the min & max cache sizes (16 & 64MB). Mostly to satisfy my power-of-two OCD.
* Purge broken on-disk cache files
* Optimize free RAM computations
* Start dropping LRU items when running low on memory before pre-rendring (hinting) pages in non-reflowable documents.
* Make serialize dump the most recently *displayed* page, as the actual MRU item is the most recently *hinted* page, not the current one.
* Use more accurate item size estimations across the whole codebase.
TileCacheItem:
* Drop lua-serialize in favor of Persist.
KoptInterface:
* Drop lua-serialize in favor of Persist.
* Make KOPTContext caching actually work by ensuring its hash is stable.
* 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.
