Allow time travel

• cvs checkout -D allows you to provide a date spec
• cvs update -d adds new directories
• cvs update -dA always gets the most recent version (head), whatever you checked out.

$ cvs checkout -D 2005-09-01 gkwr
cvs checkout: Updating gkwr
cvs checkout: Updating gkwr/db
U gkwr/db/basedata.sql
.... 
U gkwr/php/images/table-wide.jpg
$ cvs -q update -dA
P php/home.php