SF bug 480215: softspace confused in nested print

This fixes the symptom, but PRINT_ITEM has no way to know what (if
anything) PyFile_WriteObject() writes unless the object being printed
is a string.  When the object isn't a string, this fix retains the
guess that softspace should be set after PyFile_WriteObject().
We might want to say that it's the job of filelike-object write methods
to leave the file's softspace in the correct state.  That would probably
be better -- but everyone relies on PRINT_ITEM to guess for them now.

Lib/test/test_softspace.py

@@ -0,0 +1,14 @@
+import test_support
+import StringIO
+
+# SF bug 480215:  softspace confused in nested print
+f = StringIO.StringIO()
+class C:
+    def __str__(self):
+        print >> f, 'a'
+        return 'b'
+
+print >> f, C(), 'c ', 'd\t', 'e'
+print >> f, 'f', 'g'
+# In 2.2 & earlier, this printed ' a\nbc  d\te\nf g\n'
+test_support.vereq(f.getvalue(), 'a\nb c  d\te\nf g\n')