sulimmesh

Issue 4 make extensible

3

PR for making escalar more extensible for temporary ES5 support.

We currently compile against Scala 2.10 and 2.11, we should add 2.12 to this so that new projects using 2.12 can also use our client.

Adding more extensibility will make it easier for others to use escalar for ES versions beyond 1.7 until we release and official upgrade.