1.2.6: fix bug when targeting cluster on 4.0+

Oh... my... looks like FEATURE_SOCKET_MODE_POLL hasn't been defined f…

…or... a while! This is very bad

1.2.4 deploy

1.2.3 release notes

1.2.2 release notes

1.2.2 release notes

Avoid overlapped per-endpoint heartbeats and heartbeat error reports;…

… we don't want them backing up

1.2.0 release

deploy: 1.2.0-alpha1

Merge branch 'core-rtm' of github.com:StackExchange/StackExchange.Redis