Fixed documentation for variable name
Adding snapshot name to report

closes #178
Updated documentation

Only open indices are snapshotted. Documentation now mentions that.
Fix ES version edge cases with Beta1

Apparently `client.info()['version']['number']` will remove -SNAPSHOT
but not an extra .Beta1-SNAPSHOT

This makes sure only the first 3 fields of version numbers are checked.

closes #183
Update CONTRIBUTORS and Changelog