Exit gracefully on system.run() error

opendm/log.py

@@ -30,6 +30,10 @@ def ODM_ERROR(str):
     logging.error(str)
 
 
+def ODM_EXCEPTION(str):
+    logging.exception(str)
+
+
 def ODM_DEBUG(str):
     logging.debug(str)
 

opendm/system.py

@@ -23,6 +23,7 @@ def run(cmd):
     if (returnCode != 0):
         log.ODM_ERROR("quitting cause: \n\t" + cmd + "\nreturned with code " +
                  str(returnCode) + ".\n")
+        sys.exit('An error occurred. Check stdout above or the logs.')
 
 
 def now():