update requirements
refactor tests
update README.md
Merge branch 'master' into small-changes
Merge branch 'small-changes' of https://github.com/dincamihai/standard into dincamihai-small-changes

Conflicts:
	standard/schema/tests/test_validate_schema.py
	standard/schema/tests/validate_schema.py
Merge branch 'dincamihai-small-changes'