WINDUP_HOME variable handling is incorrect

1. Windup should report the current home directory as well as the version. This would make it much clearer as to which installation is actually running
2. We should override WINDUP_HOME if it doesn't match the current installation. So if they run /path/to/windup2.3 but have a variable pointed to /path/to/windup2.2 we should print a warning and run anyway
3. We should still support WINDUP_HOME to allow using the windup startup script outside of the installation directory, for people who copy it elsewhere