Rewrite 0.1.0

This is a total rewrite of the test framework.

Some of the major new features:
- Support running multiple test files.
- Support multiple assertions per test.
- Support grouping (suites)
- Add timer to see the test duration.
- Summary including assertions, runs, failures etc.
- Support skipping tests.
- Add failure information, show what was expected and what the test got.
- Add assertions for easier test writing.
- Add stubbing for functions and variables, this will restore them when the test is finished.
- And more...