Added yml parser

buildgrid/_app/cli.py

buildgrid/_app/commands/cmd_server.py

buildgrid/_app/server.py

buildgrid/_app/settings/default.yml

buildgrid/_app/settings/parser.py

buildgrid/server/actioncache/service.py

buildgrid/server/bots/service.py

buildgrid/server/buildgrid_server.py

buildgrid/server/cas/service.py

buildgrid/server/controller.py

buildgrid/server/execution/service.py

buildgrid/server/operations/service.py

buildgrid/server/referencestorage/service.py

setup.py