* fixed VZ decompressoin and add some checks
* add get_manifest() which returns a list of CDNDepotManifest for app_id and branch
* add iter_files() which will get all manifests, and iter files for app_id and branch
* add get_manifest_for_workshop_item() can be used to download steampiped hosted workshop items
* add basic caching inside CDNClient
* CDNDepotManifest, which enhances DepotManifest and inits CDNDepotFiles
* CDNDepotFile expands DepotFile to a file like object that can be used to directly seek and
read files from steampipe
* DepotFile for Manifest mappings
* CDNClient now handles content servers selection better
* CDNClient can auto get and cache cdn auth tokens and depot keys
* added get_chunk() to CDNClient, only ZIP compression, TODO LZMA
Since there are many modules, importing anything inside the steam namespace introduces an extra
cost. Cleaning up the space will allow dependent stuff to import just the modules it needs without
anything extra. This will also improve start up times for cli programs.
* remove builtin cm list
* add bootstrap_from_dns to resolve cm0.steampowered.com
* add error and logging when cm server list is empty
* add auto_discovery flag; true by default
* when CMServerList is empty it will try to bootstrap from webapi, with dns fallback
* rework SteamClient CM server persistance logic
* move discovery logic from CMServerList to CMClient
* propagate connect() return through all login methods
* detect stale persisted cm list and update
* refactor login code to handle captcha prompt better
* add cli_login() that implements the entire login flow for CLI
* renamed 'complete' property to 'logged_on' to match with SteamClient
* other minor tweaks
Rossen Georgiev
Rossen