pycrypto: fix build on darwin
weechat: fix build on darwin
pythonPackages.pync: add expression
weechat: support notification_center.py script
weechatDevel: update to latest
weechat: do not hard code python prefix
weechat: fix pythonpath
Merge #2638: fix weechat build on darwin

Conflicts (trivial):
	pkgs/development/python-modules/pycrypto/default.nix