Log Message:
py-stem: update to 1.8.0.

Stem 1.8 is the final release in Stem’s 1.x series and with it
Python 2.x support. Over a year in the making, this introduces
CollecTor, bandwidth metric, and HSv3 descriptor support.

        Controller

            Added get_start_time() method to the Controller
            Added get_uptime() method to the Controller
            Controller events could fail to be delivered in a timely fashion \ 
(ticket 27173)
            Adjusted get_microdescriptors() fallback to also use '.new' cache \ 
files (ticket 28508)
            ExitPolicies could raise TypeError when read concurrently (ticket 29899)
            Moved the arrived_at attribute from Event to ControlMessage
            STALE_DESC Flag (spec)
            DORMANT and ACTIVE Signal (spec)
            QUERY_RATE_LIMITED HSDescReason (spec)
            EXTOR and HTTPTUNNEL Listener

        Descriptors

            Added the stem.descriptor.collector module (ticket 17979)
            Added v3 hidden service descriptor support (ticket 31369)
            Bandwidth file support (ticket 29056)
            stem.descriptor.remote methods now raise stem.DownloadFailed
            Check Ed25519 validity though the cryptography module rather than \ 
PyNaCl (ticket 22022)
            Download compressed descriptors by default (ticket 29186)
            Added Compression class
            Added stem.descriptor.remote.get_microdescriptors()
            Added stem.descriptor.remote.get_bandwidth_file() (ticket 26902)
            Added DetachedSignature parsing (ticket 28495)
            Added from_str() method (ticket 28450)
            Added type_annotation() method (ticket 28397)
            Added digest() method (ticket 28398)
            Added the hash_type and encoding arguments to ServerDescriptor and \ 
ExtraInfo's digest methods (ticket 28398)
            Added the network status vote's new bandwidth_file_digest attribute \ 
(spec)
            Added is_valid() and is_fresh() methods (ticket 28448)
            Replaced RouterStatusEntryMicroV3() hex encoded digest attribute \ 
with a base64 encoded microdescriptor_digest
            Replaced the digest attribute of Microdescriptor with a method by \ 
the same name (ticket 28398)
            Default the version_flavor attribute of NetworkStatusDocumentV3 to \ 
'ns' (spec)
            DescriptorDownloader crashed if use_mirrors is set (ticket 28393)
            Renamed stem.descriptor.hidden_service_descriptor to \ 
stem.descriptor.hidden_service
            Don't download from Serge, a bridge authority that frequently timeout
            Updated dizum authority's address (ticket 31406)

        Client

            Sockets with ORPorts errored if responses exceeded a hardcoded \ 
buffer size (ticket 28961)

        Utilities

            is_valid_hidden_service_address() now provides true if a v3 hidden \ 
servie address
            Fixed 'invalid escape sequence' python 3.6 warnings (ticket 27270)

        Website

            Migrated to GitHub's issue tracker
            Added NetBSD to our download page
            Describe advanced listener usage
            Exemplify manual SAFECOOKIE authentication
            Update PyPI links (ticket 30137)

        Interpreter

            tor-prompt is now ~34% faster when used to non-interactively invoke \ 
commands