Harness enironment awareness

Add a configuration variable 'use_environment' that allows for printing of statistics and timings being dependent on harness verbosity levels.

Example:

t/blah.t:
    my $test_suite = Test::Class::Moose->new(
        use_environment => 1,
    );

prove -v t/blah.t  # shows statistics and timings
prove t/blah.t  # does not show statistics and timings