Preparing for Bigtop 3.5.0 release

[Masatake Iwasaki]

Hi developers,

I'm going to create branch-3.5 and bump the version of master to 3.6.0-SNAPSHOT
for preparing 3.5.0 release[1] shortly.
Please cherry-pick commits to branch-3.5 if it should be part of Bigtop 3.5.0
(and set the "Fix Version/s" to 3.5.0 instead of 3.6.0 on JIRA issues).

[1] https://issues.apache.org/jira/browse/BIGTOP-4459

Thanks,
Masatake Iwasaki.