46 implement yaml parsing

[K20shores]

Closes #46, closes #45

• Prefixes all build options with OPEN_ATMOS_
• Removes nlohmann::json in favor of yaml-cpp
• Duplicated all json files into a yaml equivalent and made each test parse both and ensure we get the same answers
• split out each parsers into its own file

[boulderdaze]

Looks good to me

[mattldawson]

nice!