Removed the API definition for `_search_shards`
Added the API definition for `_cluster/state`
Added the API definition for `_count`
Added the API definition for deleting a document
Added the API definition for "delete by query"
Added the API definition for `_explain`
Added the API definition for getting a document

The `_mget` API was extracted to a separate file
Added the API definition for `_mget`
Added the API definition for indexing a document
Added the API definition for deleting a single alias
Added the API definition for getting an alias
Added the API definition for `_aliases`
Added the API definition for creating or updating an alias
Added the API definition for `_analyze`
Added the API definition for `_cache/clear`
Added the API definition for closing the index
Added the API definition for creating the index
Added the API definition for deleting an index
Added the API definition for checking the index existence
Added the API definition for checking the document type existence