Fixed compilation with latest Cython version

Ignore-this: eeca6cc6f7204dbe5b7b1979a183fa7c

darcs-hash:20140331090713-56b4d-38f03143b8087d2d778903b94cc6a1a5fe41a5de
Fixed checking for minimum required Cython version

Ignore-this: 7f6eb5bc1cf3c23f4d1200ad5c01abf3

darcs-hash:20140401115830-56b4d-68106327aebcbcaf551b94536e531c07349a4b25
Initialize core from main thread

Ignore-this: d42645b2a283c2bc36b31074b1e265b6

darcs-hash:20140402112417-56b4d-72ec97bbcd4c41280e970cbee97e29e67a579710