I read the article here http://unity.ubuntu.com/getinvolved/development/unity/ about installing nux and unity to work on development. I followed the steps in the Building Nux section. I added the functions to bashrc and ran remake-autogen-project. This ran without errors. It also says that it installed in the script. I then tried to build unity and it said it was missing the nux requirement of being >=nux4.0.0. What did I do wrong not to have or install nux 4.0.0?