yaml-cpp: new package

yaml-cpp is a YAML parser and emitter in C++ matching
the YAML 1.2 spec.

https://code.google.com/p/yaml-cpp/



Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>