Scala grader

[DanG100]

Some progress towards replace the grader with pure scala. Currently it is only works with cpu tests, I have to think of a way to get it for both unit tests and cpu tests.

This is the output of the example grader which runs a few of the tests.

{ "tests":[
  {     
      "score": 10.0,
      "max_score": 10.0,
      "name": "Single Cycle Add",
      "output": "Passed add1\n" 
  },
  {     
      "score": 10.0,
      "max_score": 10.0, 
      "name": "R-type single cycle", 
      "output": "Passed add1\nPassed add2\nPassed add0\nPassed or\nPassed sub\nPassed and\nPassed xor\nPassed slt\nPassed slt1\nPassed sltu\nPassed sltu1\nPassed sll\nPassed srl\nPassed sra\n"
  },
  {     
      "score": 10.0, 
      "max_score": 10.0,
      "name": "R-type multicycle",
      "output": "Passed addfwd\nPassed swapxor\nPassed power2-512\nPassed power2-1234\nPassed power2--65536\nPassed oppsign-true\nPassed oppsign-false\nPassed rotR\n"
  }
]}

[powerjg]

Awesome! We don't have to keep the same scalatest syntax for the gradescope version of the unit tests, btw.