Grader cli specs

** All green on my machine, you previously got that error of 'receive'

Grader now parses -a, -t options.
Line 16 calls to method format_cli(args) implemented in the AutoGrader subclasses for packing hash of specs, etc.

Lots of refactoring on the specs.

Definitely can add to the Usage/Help
Perhaps add a no-op in AutoGrader to indicate the inheritance.
Could set a CLI Formatter object instead.
The features seem to require more/different dependencies, but these tests do not require Gemfile changes for me.
timeout_spec filter for warnings breaks on lowercase warning not at start of line.