send rospy-build genmsg to a different directory

[jbcpollak]

if I have a folder structure like this:

repo/foo_msgs
  +-msg/
  +-package.xml

and I run the following from repo/:

rospy-build genmsg foo_msgs/

I end up with the following directory structure, which seems counter intuitive to me:

repo/foo_msgs
  +-foo_msgs/
       +-msg/
       +-__init__.py
  +-msg/
  +-package.xml
  +-setup.py

I'm not a python packaging or ROS expert, but interleaving the output with the source directory seems really confusing to me.

Is there a best practice so I can get the generated/nested foo_msg/ folder somewhere where I can easily import it in my code just like std_msg?