Support ES 0.90.0 - mostly

Hey!

After these changes I got lein test passing with ElasticSearch 0.90.1, but had to comment `nodes-stats` because it gave me this exception:

```
Method signature problem with method indices from class class org.elasticsearch.action.admin.cluster.node.stats.NodesStatsRequest {
  :class org.elasticsearch.action.admin.cluster.node.stats.NodesStatsRequest,
  :method "indices",
  :types #{boolean org.elasticsearch.action.admin.indices.stats.CommonStatsFlags},
  :count 2,
  :all-methods [#<Method public org.elasticsearch.action.admin.cluster.node.stats.NodesStatsRequest org.elasticsearch.action.admin.cluster.node.stats.NodesStatsRequest.indices(boolean)> #<Method public org.elasticsearch.action.admin.cluster.node.stats.NodesStatsRequest org.elasticsearch.action.admin.cluster.node.stats.NodesStatsRequest.indices(org.elasticsearch.action.admin.indices.stats.CommonStatsFlags)>]}
```

Any possibility to prefer an overload with gavagai? Couldn't find any options or docs about this.

For your convenience, the overloads:
https://github.com/elasticsearch/elasticsearch/blob/master/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/NodesStatsRequest.java#L87