Rename Port to DefaultPort

Trying to prevent namespace collisions.
Fix cbdcc to handle basic "-dumpversion" like calls

We were using the index fields of the Build structure without checking for
validity, causing a panic.  The code has been re-organized to be more
clear, and use the safe access methods instead.
Use the in memory temporary file area if possible

Since we are creating a lot of temporary files this will increase
performance.  Right now this only Linux specific in that it uses /dev/shm.
Comment out debugging prints

We have reached enough stability that we no longer need these.
Work in progress on monitoring code.