Add support for "load_yaml" function to load yaml dictionary

[Garrett Johnson]

Required for parsing https://github.com/PI-PhysikInstrumente/PI_ROS_Driver.

See yaml parser here: https://www.npmjs.com/package/yaml

[Garrett Johnson]

YAML may be hard to load on the web since loading the file would have to be asynchronous but on a file system it works.