Rlease version 3.0.0

The third release candidate of 3.0.0

Second release candidate for v3.0.0

singa v3 first release candidate

Merge branch 'master' of https://gitbox.apache.org/repos/asf/incubato…

…r-singa

apache-singa-incubating v1.2.0

refer to SINGA-312

apache-singa-incubating v1.1.0 (SINGA-300 is after official release)

apache-singa-incubating v1.1.0-rc1

apache-singa-incubating-v1.0.0-rc2