Adding ZK 3.5 reconfig APIs

[jeffbean]

Supersedes #205

• changes travis tests to handle all versions of the ZK binary distribution.
• Adding new APIs IncrementalReconfig and Reconfig to support 3.5 reconfig options.

tested on ZK 3.5.4-beta 5 node zk clusters with simple add and remove actions beyond the integration tests included in this PR.

Fixes #204

[coveralls]

Coverage increased (+0.6%) to 80.685% when pulling 24d8a89 on jeffbean:reconfig-three-five into c4fab1a on samuel:master.

[coveralls]

Coverage increased (+0.6%) to 80.685% when pulling 24d8a89 on jeffbean:reconfig-three-five into c4fab1a on samuel:master.

[coveralls]

Coverage increased (+0.5%) to 80.573% when pulling d4027fc on jeffbean:reconfig-three-five into c4fab1a on samuel:master.

[msolo]

There are a lot of good changes in this PR. I've been integrating improvements to the upstream: https://github.com/z-division/go-zookeeper/wiki

[jeffbean]

https://github.com/z-division/go-zookeeper/wiki

Thanks,
I am also working on more fixes and do intend to communicate a plan from my end on how I intend to hard fork this library. It will take a bit of time as I want to ensure folks have some time to respond to my posts and PR before taking any real action, as well as figure out the best course to do so.

If you are looking for more improvements my personal fork master branch has some more testing and bug fixes :D

[samuel]

Thanks for the change. I'm not actively maintaining this repo as I haven't used Zookeeper for a very long time, but I'm trying to go through and get some of these changes in just in case there's anyone still relying on this package.