solved BAD_EXEC_ACCESS on [readStream open] or [writeStream open]
issue #4

refer:
http://stackoverflow.com/questions/20111643/exc-bad-access-sigsegv-when-uploading-with-ftp-library-on-ios-cfwritestreamop
Merge pull request #15 from t-oginogin/solved_BAD_EXEC_ACCESS_on_stream_open

solved BAD_EXEC_ACCESS on [readStream open] or [writeStream open]