The new API will now be found in the repository yaml-cpp.new-api

Renamed the base64 methods, and switched the EncodeBase64 one to return a string (to make it easy to use elsewhere)

Refactored the base64 binary to its own space with a unified class that (will) be used for parsing (in addition to emitting)

Updated new API conversion to handle nan/inf and to throw when the conversion didn't use the entire string (e.g., parsing 1.2 as an integer)

Removed some extra stuff in the comment/newline in flow map tests, which really should be illegal (since implicit keys can't span multiple lines). It would be impossible to fix if we keep the immediate-output we're doing now - the only way to prevent it would be to hold on to a key's text until we got to the value token to make sure it could be an implicit key

Added explicit conversion from an iterator value to a Node. This conversion was always allowed (since the iterator value is derived from Node, but since Node has a templated constructor, that would take precedence over the derived-to-base conversion. This didn't seem to be a problem in gcc or clang, but MSVC seems to have trouble. (new API)

Fixed compiler error in iterator_base friend forward declaration in node on clang (and I hope MSVC), plus warnings on clang

Set the default operator >> to not compile unless there is a scalar conversion, so it doesn't interfere with user-defined types