Fixed LUSERS count not subtracting invisible users

update developing documentation

fix fakelag double-rate issue

Basically, fakelag was counting the time imposed by its own sleeps as though
the user had themselves paused for that amount of time. Therefore, if a user
sent a large number of consecutive commands, every other command would pause
for the expected throttle interval, but the subsequent command would be
processed instantly (you'd get two back-to-back commands). This resulted in
throttled users being able to send at double the expected rate.

Updates to channel persistence

more tweaks to letsencrypt documentation

FAQ Section: Let's Encrypt

know people have problems/questions

this probably takes care of #118 and #231 well enough to at least
resolve them and start using the md/docs

genpasswd confirmation of entered password

fix #227

1. Implement persistent channel keys (#208)
2. Persist changes to registered channel modes
3. Backend changes for persisting operator status (partial #198)