Moving the common part of the html files into one file.

[mailhexu]

Currently many of the html files include the same content (for example, links on the header of the page). We can move these into one file and link to the file instead of copying them in every html file. This increase the maintainability: we don't have to modify every file if something is to be changed.
I can write a script to do that.
HeXu