link to mailing list in README (why did I not do this before)
update README to fix outdated info relating to manifest authentication
login: don't print 'enter password' prompt when password has been given on CLI
get_client: add support for downloading VZ files

this commit also decomposes all of the downloading logic into separate
functions to avoid duplication (and to make it easier to understand)
login: make it clear which password we need
depot_archiver: fix for new-style manifest appinfo
login: comment out key-saving stuff

steam updated their login process which broke the valvepython steam
library's support for saved login keys. disable saved logins until
upstream fixes it
depot_archiver: request free licenses
handle app tokens in depot_archiver and get_depot_keys
get_depot_keys: add app and depot arguments
depot_archiver: add option to download into csd
use the Chunkstore class for all operations on chunkstores
unpack_sis: remove accidentally left breakpoint
depot_extractor: don't hexlify chunk SHA twice
depot_extractor: implement extracting chunks directly from a chunkstore
login: save auth if run directly
update readme example
login: make auth directory before attempting to save CM server list
diff_manifests: fix accidentally printing old chunk counts for new files