initialise all fields to 0 when using object structs from the freelist

--HG--
extra : rebase_source : 346e99306b247c116d988b58802ed7e7eb62754c
use a couple of branch prediction macros in tp_new() function, just in case

--HG--
extra : rebase_source : 32ab400fc7cf381d2267ae01b3ada7065d706ed2
delete unused file

--HG--
extra : rebase_source : 3998c84c9c2a646d9588103205666d37731c41a7
properly integrate pyximport into setup.py

--HG--
extra : rebase_source : d0e52d3a06b2734287cc30fe9ef9ebd0a641b05a