* Use unittest2 test runner
Since upgrading to unittest2, the test runner prints the command line to
re-run a failed test - this however relies on actually using the
unittest2 command line runner.
Previously, test files were assigned numbers - with the unittest2
runner, tests are run using suite/category names instead, like so:
```
# run the Genesis suite
build/all_tests "Genesis::``
# run all tests with "blsMapG1" in the name
build/all_tests "blsMapG1*"
# run tests verbosely
build/all_tests -v
```
A reasonable follow-up here would be to review the suite names to make
them easier to run :)
* lint
* easier-to-compare test order
* bump unittest2 (also the repo)
now macro assembler support merge fork, shanghai, etc without using ugly hack.
also each assembler test have their own `setup` section that can access
`vmState` and perform various custom setup.
* Reduce Nim 1.6 compiler warnings/hints for Fluffy and Nimbus proxy
Mostly raises Defect removals, TaintedString removal and some
unnecessary imports.
Also updating the copyright years alongside.
* Further reduce Nim 1.6 compiler warnings/hints for Nimbus
