Refactor Add-Activity

Move AddActivityAction to model. Just provide a interface to controllor.
Show Activities

modified:   ../strutslogin/WebRoot/eating/eating.jsp - Add dynamic contents.
modified:   ../strutslogin/src/com/hsp/model/Activity.java - Add method to get formatted time.
new file:   ../strutslogin/src/com/hsp/model/QueryAllAction.java - Query all contents of 'activities'.