* let the user make more formatting choices

* test for debug option

* option to print scalar values like:
        Scalar 16 bytes ('a')
        'a' => Scalar 16 bytes ('123')
        'f' => Scalar 16 bytes ('0.23')

* plain scalars do not yet print their address (make that an option)

* document how to wrap your own report_size function

* add a report_size_in_html() function? Or make generic "string-hooks" that
  can be used to have a $preamble etc?

* [ 1,2] is technically a ref to an array, \[ 1,2 ] is technically a ref to
  an array ref. Currently, the first is reported as "Array ref", the second as
  "Array ref Ref". The second case should be different (like "\1").

* $x = 'a scalar'; report_size(substr($x,0,2), {}) prints:
  Size report v0.06 for 'a ':
    Scalar 115 bytes
  Total: 115 bytes

  While Devel::Peek says:
  SV = PVLV(0x81a9598) at 0x829d568
    REFCNT = 1
    FLAGS = (PADMY,GMG,SMG,pPOK)
    IV = 0
    NV = 0
    PV = 0x82b3db0 "a "\0
    CUR = 2
    LEN = 3
    MAGIC = 0x82b4f30
      MG_VIRTUAL = &PL_vtbl_substr
      MG_TYPE = PERL_MAGIC_substr(x)
    TYPE = x
    TARGOFF = 0
    TARGLEN = 2
    TARG = 0x829d520
    SV = PV(0x82a5018) at 0x829d520
      REFCNT = 2
      FLAGS = (PADBUSY,PADMY,POK,pPOK)
      PV = 0x82b2648 "a scalar"\0
      CUR = 8
      LEN = 9

   Surely our report could be better, and at least say "Magical Scalar".

   (There is now SF_MAGIC(), but there doesn't seem to be any way from Perl
    or Devel::Peek to ask for the equivalent of is_magic($scalar)...)