GitLab

Fixed new API node key/value insertion in NodeBuilder (it was using the wrong condition on when it had added a key already)

Major switch from Value -> Node. The library compiles with the new API, but tests are still oldies, and don't compile

Switched the 'pragma once' to only happen on MSVC, or gcc >= 3.4 (it was causing trouble on the sun compiler)

Flipped the include guard and the pragma, and don't use the pragma for early versions of gcc (< 3.4)

Moved all the includes to a subfolder yaml-cpp so they don't interfere with other libraries' includes