Enforce integer base limits of 2 to 64 (#139)

src/cmd/ksh93/bltins/typeset.c: b_typeset():
- For integer bases change argnum check to default values that
  are < 2 or > 64 to 10 instead of allowing invalid base values
  that ksh cannot process.

src/cmd/ksh93/bltins/typeset.c: setall():
- Remove argnum check for integer base of 1 as base cannot be 1.
- Relocate strlen(name) to inside of conditional check for
  np->nvfun as this code does not need to run all.
- Remove no-op oldname code

src/cmd/ksh93/tests/attributes.sh:
- Add typeset -i base bounds checks to default base 10

src/cmd/ksh93/tests/attributes.sh

@@ -552,5 +552,13 @@ do	unset foo
 done
 unset expect
 
+unset base
+for base in 0 1 65
+do	unset x
+	typeset -i $base x
+	[[ $(typeset -p x) == 'typeset -i x' ]] || err_exit "typeset -i base limits failed to default to 10 with base: $base."
+done
+unset x base
+
 # ======
 exit $((Errors<125?Errors:125))