Fixed some minor bugs and have helpful debug messages now

wetb/hawc2/hawc2_simulation.py

@@ -267,6 +267,8 @@ class Hawc2_Simulation(object):
         old_home = os.getcwd()
 
         # Change to the htc directory
+        if not os.path.isdir(self.write_directory):
+            os.makedirs(self.write_directory)
         os.chdir(self.write_directory)
 
         # This is the point where you would specify that a file is running
@@ -431,7 +433,8 @@ class Hawc2_Simulation(object):
             key = key[len('hawc2_output.'):]
             return self.results[key]
         else:
-            raise KeyError('That key does not exist')
+            error_message='The key "%s" does not exist'%(key)
+            raise KeyError(error_message)
 
     # Set some information from on the object
     def __setitem__(self,key,value):