Reconstitution 20140313

1.move each class to single file in /session/class/, and rename as
“class_**.php”
2.move page files to /session/page/, and rename as “page_**.php”
3.move global variables to /session/global_variable/. there is only one
variable for now, $os=“linux”
3.move old files to /session/backup/
4.fix bug in the old version of page.php
Merge pull request #2 from yeahu/master

Reconstitution 20140313