[script] Add significance test and support for it on evaluation

bob/ip/binseg/engine/evaluator.py

bob/ip/binseg/script/compare.py

bob/ip/binseg/script/evaluate.py

bob/ip/binseg/script/significance.py

bob/ip/binseg/test/test_cli.py

conda/meta.yaml

doc/cli.rst

doc/links.rst

doc/usage.rst

requirements.txt

setup.py