Add function to create xml from yaml input

The bulk of this commit is just including the yaml module. 

The real meat of my code is in interface.py, where I created a function create_xml_from_yaml() which does what the name says. I also modified globs to call this function only if an xml input (Input.xml) is not found in genetic/seeds. In order to see the function run, make sure you have the Input.yaml file, then delete Input.xml, then run. Input.xml should be created and scheduler should run normally.