add discovery client

Feature: Add always_print_primitive_fields flags into Controller and …

Update .bazelrc

set ture if dumps all fields to json in protobuf3.

Support Prometheus output

update avalanche.md

string_splitter supports embedded '\0' characters and separator can be '\0'

bug fix: consul ns thread can not quit

wrr lb algo enhancement

Update server.md

删除错别字。

fix a typo in docs

circuit_breaker optimization