Writes to memory location 0xf0000000 output on stdout

Add hello.cpp which creates a program that outputs "hello":
    ./hello | ./sim

Add "Success" and "Failure" output to memory_test
    ./memory_test | ./sim
    It succeeds as of this commit; comment out the AND to watch it fail

Print number of instructions executed; on my 2.6GHz MacBookPro, I get about 100M instructions per second, so I suspect we can beat the FPGA

Add verbosity setting and squelch most sim output
    ./memory_test | ./sim # print only output from interpreted program
    ./memory_test | ./sim --verbose=2 # print number instructions executed
    ./memory_test | ./sim --verbose=3 # print everything

Add memory faulting to sim.cpp
    memory access outside RAM set a memory fault flag, halt, and print a msg

Catch byte write to 0xf0000000 in sim.cpp and putchar that byte

Break out memory class, test memory class implementation, and jmp vector utility function into util.cpp

Set LOAD and STORE to use 18 bits of data in sim.cpp

I think I need to stop.