Monitor UCD90160 for faults at runtime

Add the RuntimeMonitor class that will monitor the
UCD90160 faults in 2 ways:

1) Watch for the PowerLost signal, meaning system
   PGOOD was lost.  When it occurs, analyze the
   chip for errors and then issue a proper shutdown
   so a faulted device doesn't keep getting power.

2) Poll on an interval for nonfatal errors that need
   to be logged but don't cause a PGOOD loss.

The main executable can now launch either the PGOODMonitor
or the RuntimeMonitor based on commandline arguments.

Change-Id: If2856f173d5d6288d8333538334b4b4cb4a60097
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/power-sequencer/argument.cpp b/power-sequencer/argument.cpp
index d668de1..e76adce 100644
--- a/power-sequencer/argument.cpp
+++ b/power-sequencer/argument.cpp
@@ -28,8 +28,12 @@
     std::cerr << "Usage: " << argv[0] << " [options]\n";
     std::cerr << "Options:\n";
     std::cerr << "    --help                Print this menu\n";
-    std::cerr << "    --action=<action>     Action: pgood-monitor\n";
-    std::cerr << "    --interval=<interval> Time to allow PGOOD to come up\n";
+    std::cerr << "    --action=<action>     Action: pgood-monitor "
+                 "or runtime-monitor\n";
+    std::cerr << "    --interval=<interval> Interval in seconds:\n";
+    std::cerr << "      PGOOD monitor:   time allowed for PGOOD to come up\n";
+    std::cerr << "      Runtime monitor: polling interval.\n";
+
     std::cerr << std::flush;
 }