fix the bug caused in HA cluster in consumer (apache#723)

fix the bug caused in HA cluster in consumer (apache#723)

(cherry picked from commit 4065610)

[ISSUE apache#568] Update lastPullTime use atomic.Value as same with …

…lastConsumeTime and lastLockTime (apache#613)

[ISSUE apache#568] Update lastPullTime use atomic.Value as same with …

…lastConsumeTime and lastLockTime (apache#613)

fix(nameserver): panic in nameserver size is changed. (apache#529)

Support log level set and add more log in offset. (apache#489)

* Add log print for offset manager by broker

* modify log level for offset

* Support log level set

[ISSUE apache#473] support nsresolver in TraceConfig

keep NamesrvAddrs config and add Resolver for TraceConfig

[ISSUE apache#473] support nsresolver in TraceConfig

keep NamesrvAddrs config and add Resolver for TraceConfig

feat: support nameserver resolver (apache#457)

use nameserver resolver instead of nameserver address, we can pass
passThrough for direct address, httpResolver for a domain, an env resolver
for env param.

modify version and readme to release 2.0.0 (apache#469)