Merge pull request #18 from r--w/master

Handling errors in bulk indexing.
Support for PutMapping API
HEAD requests have no body, only HTTP response code, so we need to act accordingly
Test IndicesExist
IndicesExist implementation
go fmt
ignore vim files
Update API implementation
Update test
Unmarshal whole response into Raw field on Response for APIs that return fully dynamic format, like _mapping
GetMapping implementation
Give ES some time to work in tests
Use slices instead of variadic function
Only set Id on document if it was given
Merge pull request #19 from marinbek/master

Support for PutMapping, Update and IndicesExist APIs