Note to all users on Ubuntu 12.04, one of the dependencies is not available (osrf-pycommon) through the debian package system. We are working to fix this, but if you want to try out catkin_tools 0.4.0 before then, you can still install it via pip or from source:
Additionally, if you encounter problems with the second beta, you can still install the previous release (0.3.1) with pip:
pip install -I catkin_tools==0.3.1
Thanks for the great feedback we're already getting!