Adds update code for homework 5

Does exactly what the title says.  Also fixes a bug in syscallOpen.
Implements all parts (tentatively)

Code as-is does not spawn all processes.
Fixes process 1001 premature killing
Fixes comments, debugPrintlns, and a syscallRead bug.
Adds helper methods to clean code

Added a quasi-overloaded push method the the ProcessControlBlock.  Added
a decrementPC method to the CPU.
Adds author, fixes whitespace.

Adds author tag for Dan Nelson to CPU.java
Fixes whitespace issue in declared constants for SOS.java