Convenient user aliases and foamPwd

I have been discussing with Mark Olesen that it would be convenient with some user aliases to move to the user directory, more than the 'run' alias. I often want to go to $WM_PROJECT_USER_DIR/{applications,src} and $WM_PROJECT_USER_DIR/applications/{solvers,utilities}. I have also suggested a foamPwd command, which is the same as pwd, but gives an output with OpenFOAM environment variables. It may be in particular be convenient for those who are learning to use the environment variables. I use it for teaching, where my prompt is set using such a command. Then the prompt gets much shorter, and the students understand that the environment variables are useful when moving around in the directories.