Read from file (--input).

Read input from file (--input).
Change the signature of multiplex().

Signed-off-by: Rudá Moura <ruda.moura@gmail.com>
Add a YAML parser that can be used with multiplex.

Examples:

multiplex.py $( ./parse_yaml.py example.yaml )

or

parse_yaml.py example.yaml > variants.txt
multiplex.py --input variants.txt
multiplex.py --input variants.txt --filter-only /tests/sleeptest

Signed-off-by: Rudá Moura <ruda.moura@gmail.com>