lots of wide-string stuff

Rev: bin/test_pike.pike:1.14
Rev: src/array.c:1.41
Rev: src/builtin_functions.c:1.129
Rev: src/modules/sprintf/sprintf.c:1.28
Rev: src/operators.c:1.43
Rev: src/pike_memory.c:1.27
Rev: src/stralloc.c:1.43
Rev: src/stralloc.h:1.21
Rev: src/testsuite.in:1.126