remove the document-object-interface in favor of http://www.elasticsearch.org/guide/reference/mapping/id-field/
Merge pull request #386 from lsmith77/remove-document-object-interface

remove the document-object-interface
Elastica\Index::exists fixed for 0.90.0. HEAD request method introduced
Update to ES 0.90.0 for travis
Elastica\Filter\AbstractMulti::getFilters() added
Verify with test that Elastica\Index::count($query) works as expected
Implement Elastica\Type\Mapping::enableAllField
Refresh for Elastica\Index::flush implemented #316
Filtering queries while percolating #384