add several new functions that can be called from the guest

add several new functions that can be called from the guest
to tell the simulator to do something.
exit -> exit_old (deprecated
exit now takes an optional parameter that tells it to execute at a
specified time in the future

The next four functions have two optional parameters.  The first
specifies a delay for how long to wait to issue the instruction.
The second will tell the simulator to repeat that command
at the specified interval.

checkpoint will trigger a checkpoint
dumpstats will cause the simulator to dump stats
resetstats will cause all stats to be reset
dumpreset will dump and reset stats

all times are in nanoseconds

util/m5/Makefile:
    Clean up to make it a bit easier to muck with
util/m5/m5.c:
    Add a bunch of new commands and clean up the command parsing path
    Convert atoi to strtoul so that we can use 64bit numbers and even
    hex if we want to.  (this runs on alpha, so a long is 64bit)
util/m5/m5op.h:
    add prototypes for new m5 instructions
    use uint64_t since it's nicer

--HG--
extra : convert_revision : 664ff00f0f0dfc5263c4e873d82fd9996a4521e9