* Made TagLibrary a ref object
* Started writing fastparse.nim, a parser aimed to deliver
much faster speeds than the current implementation. It
currently is only able to parse block content
* Added YamlWarningCallback that may be used to capture
parser warnings
* Removed yamlWarning as event kind
* Replaced checks for well-formedness in presenter with asserts
* Added checks for JSON compatibility of YamlStream in presenter
* Added proper type hints for special float values in
serializer to be able to check for them in the presenter
Felix Krause