Changes to functions from blender/windowmanager/intern/wm_event_system.c

Python operator api was using WM_operator_name_call() which was confusing things too much.
Added WM_operator_call_py() which ended up being a very small function and split out operator creation into wm_operator_create()

Python operator now runs the poll() function and raises an error if it fails.

Eventually there should be error messages for poll that python can use to give the exact reason for failing (eg - library linked data, no active object...)

source/blender/python/intern/bpy_operator.c

@@ -194,6 +194,11 @@ static PyObject * pyop_func_call(BPy_OperatorFunc * self, PyObject *args, PyObje
 		return NULL;
 	}
 	
+	if(ot->poll && (ot->poll(self->C) == 0)) {
+		PyErr_SetString( PyExc_SystemError, "Operator poll() function failed, context is incorrect");
+		return NULL;
+	}
+	
 	WM_operator_properties_create(&ptr, self->name);
 	
 	error_val= PYOP_props_from_dict(&ptr, kw);
@@ -203,7 +208,7 @@ static PyObject * pyop_func_call(BPy_OperatorFunc * self, PyObject *args, PyObje
 
 		BKE_reports_init(&reports, RPT_STORE);
 
-		WM_operator_name_call(self->C, self->name, WM_OP_EXEC_DEFAULT, &ptr, &reports);
+		WM_operator_call_py(self->C, ot, &ptr, &reports);
 
 		report_str= BKE_reports_string(&reports, RPT_ERROR);