Add license GPLv3

GPL-3.0.txt

build_formula.py

create_pool.py

html_cooker.py

master_of_peppets.py

meta_parser.py

plat_tags.py

py_sat.py

satisfy_req.py

tests/test_meta_parser.py

tests/test_satisfy_deps.py

tests/test_versions.py

thief.py

versions.py