Address issue 239: Dict constructors on typed data but without explicit type declarations
    should no longer return {Any,Any} items because collect is now used when explicit types
    are omitted

    Address issue 479: Deprecate insert!, pop!(s), introduce popfirst!, poplast!,
       ss_push!, sd_push!, smd_push!

    Address issue 528: push! documentation improved

    Address issue 667: Docs extensively cleaned up and much greater use of
      documenter.jl

    Address issue 669: Expanded use of tokens including a:b notation for tokens

    Address issue 671: Add reverse iteration

    Address issue 742: New union, merge, symdiff, setdiff, intersect algorithms for
    sorted containers to improve performance

    Address issue 726: Clarify docs on insert! (now deprecated)

    Address issue 767: Implement firstindex, lastindex, reverse for sorted container iteration

    Address issue 781: Use collect on an intermediate step
    to infer types in untyped construction of sorted containers

    Also, this commit cleans up the constructors and
    adds two new iteration-helper functions inclusive_key
    and exclusive_key that were useful in my own work.

…uccessful parse

  Renamed push_return_token! to push_return_semitoken!, which accurately
  describes the operation.

  Documented the fact that values(s) is not currently writeable.