GitLab

Fixed when we emit the doc start (only if there already is a document in the stream, and we're about to emit a new node)

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