fix analysis of entry to be a weakref (typo introduced in d96dfd)

Originally reported in Debian http://bugs.debian.org/cgi-bin/bugreport.cgi\?bug\=692313
Lead to crash with python-dbg:

  python-dbg: ../Modules/gcmodule.c:366: visit_decref: Assertion 'gc->gc.gc_refs != 0' failed

Minor cleanup of a couple of examples

- fixed wrong references (The file on the left (right) -> actual file name)
- divided an example snippet of three files into separate files

Fixed indentation of a code example

Fixed a code example which had been indented with 2 spaces.

changed file order in Sharing C Functions example

This order looks more logical, easier to read.

--HG--
extra : transplant_source : %CC%EC%23%19%11%1A%22%FB%5C-%18%AD%0D%FC%24L%BD%81%91%FF

Update cy break examples

add platform specific include directory to compile line

beginning with python3.3 it is different than the general include
directory on debian based systems

--HG--
extra : transplant_source : %08%F6%88rE%C7%F5%CD.%9Ad%244m%0Cw%8C%25g%C0

--HG--
extra : transplant_source : %01%22lN%B0%1D%B9h%AC%2B4%E1F%7FQ%15%E6%F3%F1%9F

--HG--
extra : transplant_source : 81Y%F6%E5%B8%BF%F4%D9%97%85%93%16%9B%A5E%B2%FD%AE%5C