This command sets the working area and project for the current user.
http://www.myserver.com/evj/ExtraView/ev_api.action?
user_id=username
&password=password
&statevar=set_area_proj
&area_id=nnn1
&proj_id=nnn2
Both the area_id and the project_id must exist, else the command will fail.
The proj_id must be valid within the area_id, else the command will fail.
