Add CPython 3.4.2rc1 (fixes #245)

plugins/python-build/share/python-build/3.4.2rc1

@@ -0,0 +1,3 @@
+require_cc
+install_package "readline-6.3" "http://ftpmirror.gnu.org/readline/readline-6.3.tar.gz#56ba6071b9462f980c5a72ab0023893b65ba6debb4eeb475d7a563dc65cafd43" standard --if has_broken_mac_readline
+install_package "Python-3.4.2rc1" "https://www.python.org/ftp/python/3.4.2/Python-3.4.2rc1.tgz#6cec49a0dccccce78841d62e7fec0aa60a52e6640fd65e61fcce83b24e0c6962" ldflags_dirs standard verify_py34 ensurepip