Added a logger for more maintainable and configurable debug messages.

Fixed a bug with context setting so that all children are updated on
context update.

jgui/logger/__init__.py

@@ -0,0 +1 @@
+from jgui.logger.logger import *

jgui/logger/logger.py

@@ -0,0 +1,6 @@
+from __future__ import print_function
+from jgui.settings import DEBUG
+
+def log(*args):
+    if DEBUG:
+        print(*args)