KNOWN LIMITATIONS (BUGS):
1.	Each time a new element access is made Tcl creates the element
	in the array's hash table.  Currently these are not freed until
	the object is destroyed.  This could lead to memory starvation,
	especially with big arrays.
2.	Initializers ("init") are not yet implemented.
3.	Justification is not yet implemented.

FEATURES TO BE ADDED:
1.	$obj(5-7)
	Should create an array that points to just the three elements.
2.	Add aggregate types to "structtypes" manual page.
3.	Write an "intro.n" manual page with an overview
4.	Allow "user-defined" types?
		call user trace routine for formatting
5.	"init <value>"
	use when initializing structure
6.	"fill <value>" on _hex_ to work like _char_ fill?
7.	Create Struct_InitObject(interp,object) to initialize an object
	based upon the "fill" and "init" values.
8.	Implement justification with char arrays (and hex?) and arrays
	in general.  The default justification is "left".
9.done	If NULL_OK is set for char*fill, then don't space fill when the
	empty string is written to the field?
	Need to document this.
10.	cdata in tclStruct.c is not always the same thing.  Change the
	different ones to use different names.
