Widget framework added

Hi, glog has been added a widget framework.

A theme can define widget groups as widgets container for show widgets on page. Template variable "wgroup1...n" which is list of widget string will be pass to template engine. Theme can fetch widget content from URL like "/blogId/widget/widgetid/widget_param" by ajax or something else.

User specify which widgets will be shown and group them by a simple rule.

Widget developer just need write a python module, import the widget module define a module function and register it. Of course, developer must write a templete file for this widget named "widgetid.widget".

I'll give some example later. But if you read the source you'll find that Tags cloud, Archives list, Blog infomation, RecentComment has implemented as widget.