Display import errors in the GUI as well as the terminal, issue 789, thanks Marc

gluon/messageboxhandler.py

@@ -0,0 +1,15 @@
+import logging
+
+try:
+    import tkMessageBox
+except:
+    tkMessageBox = None
+
+class MessageBoxHandler(logging.Handler):
+    def __init__(self):
+        logging.Handler.__init__(self)
+
+    def emit(self, record):
+        if tkMessageBox:
+            msg = self.format(record)
+            tkMessageBox.showinfo('info1', msg)