code changes for array conversion.

code changes for array conversion.
as a reminder, the old conversion
was that you could write

	var arr [10]byte;
	var slice []byte;
	slice = arr;

but now you have to write

	slice = &arr;

the change eliminates an implicit &, so that
the only implicit &s left are in the . operator
and in string(arr).

also, removed utf8.EncodeRuneToString
in favor of string(rune).

R=r
DELTA=83  (1 added, 23 deleted, 59 changed)
OCL=27531
CL=27534