* Changed many files to use mkvalue() instead of newtupleobject().

* Fixcprt.py: added [-y file] option, do only files younger than file.
* modsupport.[ch]: added vmkvalue().
* intobject.c: use mkvalue().
* stringobject.c: added "formatstring"; renamed string* to string_*;
  ceval.c: call formatstring for string % value.
* longobject.c: close memory leak in divmod.
* parsetok.c: set result node to NULL when returning an error.