Change es version to 1.0.0.RC1

* Move RestRequest to be an abstract class https://github.com/elasticsearch/elasticsearch/issues/4683
* Change the version of es to 1.0.0.RC1
* Related DateFieldMapper https://github.com/elasticsearch/elasticsearch/issues/3806 , https://github.com/elasticsearch/elasticsearch/issues/4560 , https://github.com/elasticsearch/elasticsearch/issues/4079 , https://github.com/elasticsearch/elasticsearch/issues/4117 , https://github.com/elasticsearch/elasticsearch/issues/4521
* Redesigned the percolator engine https://github.com/elasticsearch/elasticsearch/issues/3173
Merge pull request #1 from johtani/change-to-es-version-1.0.0.RC1

Change es version to 1.0.0.RC1