Switched getting the initial chat messages to the new chat engine
Use UTF-8 by default in HTTP client to retrieve string contents
Introducing chat message's seq number whenever it's needed
HttpChatClient.requestMessages() is split into 2 separate messages for last and new records
HttpChatClient.requestMessages() is split into 2 separate messages for last and new records
Introduced HttpChatClientTest, moved message parsing tests there
HttpChatClient tracks last message seq when retrieving last messages
HttpChatClient uses internal last message seq to make requests
Removed unused chat message seq references outside of HttpChatClient
Removed unused chat message seq references outside of HttpChatClient
Removed unused chat message seq references outside of HttpChatClient
HttpChatClient - simplified public interface
Minor changes