Expycted

Changes:
- File-system matchers
- Refactoring for more internal structure

Changes:
- Adding type hints
- Refactoring some logic

Changes:
- Adding function matchers `to_raise` and `to_return`
- Adding aliases for value matchers

Changes:
- Adding matchers `equal`, `be`, `be_greater_than`, `be_lesser_than`, `be_greater_or_equal_to`, `be_lesser_or_equal_to`, `is_numeric`, `contain`, `be_contained_in`, `be_empty`, `be_true`, `be_false`, `be_turthy`, `be_falsey`, `be_of_type`, `inherit`
- Proper test coverage