Add ability to limit the number of results (and order them)

[patrickmcelwee]

• Limit options
  • Ability to select n for limit
  • Ability to select n for document skipping (offset)
  • Ability to sample n documents
  • Ability to "truncate"
• Ordering options
  • Ability to choose frequency-order instead of item-order
  • Ability to choose between item-frequency and fragment-frequency

There should automatically be some sane limit (like 10?), perhaps with ability to paginate.