add remote upload buffer (--remote-buffer)
- added new option --remote-buffer
- allow to_send to grow to selected size
- don't grow if wait is specified
- fill pipe on any command (including 'async_response')
- add new option to docs
- create EfficientBytesQueue to prevent recreation of buffer each time we send something
- add tests for EfficientBytesQueue
- Group options
- Nicer list of options in Sphinx
- Deduplicate 'Common options'
(including --help)
The latter is done by explicitly declaring --help in the common_parser,
which is then inherited by the sub-parsers; no change in observable
behaviour.