Created model + method name changes

Created classes to model the chat rooms.
Overrode equals and hashcode in ChatRoomInfo
Made some changes to method names in ChatManager to reflect new hungarian prefixes.
*introducing new hungarian prefix, crm -> ChatRoomModel*

AddedFiles:

HallwayModel.java - contains map from cri to crm, and relevant operations.
ChatRoomModel.java - contains set of users, list of messages, and relevant operations.

Modified Files:

ChatManager.java
ChatRoomInfo.java

SubmittedBy: Cory Shiraishi