[Nickle]Nickle: new builtins

[Barton C Massey]

New builtins checked into nickle:

  New scope strings, with functions
    int length(string)
    int index(target-string, match-string)
    string substr(target-string, start-index, length)
  All of these have essentially the AWK semantics,
  except 0-based instead of 1-based.

  int dim(array)
    Number of elements in a 1-dimensional array.
  array dims(array)
    1-dimensional array of n elements giving
    each dimension in an n-dimensional array.

I'll get the library autoloader installed and re-install the
rest of the PRNG shortly.  I'll probably also slightly clean
up the nickle command-line argument handling here shortly.

Have fun!

		Bart