Uses util.inspect in base reporter to support show diff of circular object

showing diff of objects which contain circular object, instead of silently fail.

    actual expected

       1 | { id: null,
       2 |   name: 'Root',
       3 |   meta: null,
       4 |   categories:
       5 |    { aab:
       6 |       { id: 'aab',
       7 |         name: 'A',
       8 |         meta: null,
       9 |         categories: [Object],
      10 |         sources: [Object],
      11 |         parent: [Circular] },
      12 |      c:
      13 |       { id: 'c',
      14 |         name: 'C',
      15 |         meta: null,
      16 |         categories: {},
      17 |         sources: {},
      18 |         parent: [Circular] } },
      19 |   sources: {},
      20 |   parent: null }

    expected { id: null,
    name: 'Root',
    meta: null,
    categories:
     { ab:
        { id: 'ab',
          name: 'A',
          meta: null,
          categories: [Object],
          sources: [Object],
          parent: [Circular] },
       c:
        { id: 'c',
          name: 'C',
          meta: null,
          categories: {},
          sources: {},
          parent: [Circular] } },
    sources: {},
    parent: null } to equal { id: null,
    name: 'Root',
    meta: null,
    categories:
     { a:
        { id: 'a',
          name: 'A',
          meta: null,
          categories: [Object],
          sources: [Object],
          parent: [Circular] },
       c:
        { id: 'c',
          name: 'C',
          meta: null,
          categories: {},
          sources: {},
          parent: [Circular] } },
    sources: {},
    parent: null }