Update generated services

* Fix default handling for int64
Update version to 0.1.15
Update version to 0.1.16
Pass etag parameter in GapiService.put and GapiService.patch
Update generated services
Update version to 0.2

Replace json-wheel with yojson
Update README
Add flag all to _oasis
Clean _tags and _oasis (dependencies)
Remove unneeded xmlm dependency from gapi-ocaml
Pretty print saved service document
Update Discovery and Drive services
Update Drive Model (appDataContents)
Modify service generator
* Merge different enum values into the same module for parameters
  with the same name
* Add documentation to enum values
Update version number to 0.2.1
Update generated services
Apply patch by Christophe Troestler
Update generated services
Escape reserved characters in ocamldoc documentation
Make Unauthorized and ServiceUnavailable exceptions public