dependencies: rm "pylru" dep, instead inline stripped-down "cachetools"

[SomberNight]

closes #247

[ben-grande]

That was quick, thanks. Checked out your branch or a new install:

INFO:Prefetcher:catching up to daemon height 828,405 (720,366 blocks behind)
INFO:BlockProcessor:our height: 108,049 daemon: 828,405 UTXOs 0MB hist 0MB
INFO:BlockProcessor:our height: 109,049 daemon: 828,405 UTXOs 1MB hist 3MB
INFO:BlockProcessor:our height: 110,049 daemon: 828,405 UTXOs 3MB hist 5MB

All seems fine. Should I check something specific?

[SomberNight]

The caching is only used for serving client sessions, and you seem to still be doing initial sync.
Anyway, I've tested it a bit now.