Parse new-style "Nested Schema" sections in markdown docs (#345)
* WIP on parsing newstyle md docs
* Inching closer on parsing param descriptions
* Hack new-style parser into the old parser
* Warn instead of panic
* Cleanup parse_markdown, add doc headers
* Test and clean up a few oddities
* Add tests for nested map parsing
* Complete one TODO
* Also parse top-level Schema
* Handle top-level and nested together
* Fixup description parser
* Skip some more redundant things
* Fix request_max_bytes parsing as request*max*bytes
* Parse top-levels as Attributes not Arguments
* Try to normalize windows line endings to unix before parsing tests
* Fix
* Add CHANGELOG entry
