Completed chat functionality

-Created get_chat(ajax request to get data), display_chat(append data to the content div through Handlebar), and refresh_chat(executes get_chat in intervals)
-Separated display_chatbox from display_chatbox in both chat.js and index.html Handlebar scripts so that refresh_chat does not affect the chatbox, where you type the message
-Changed display_chat to use before instead of append since display_chatbox gets executed first
-Created send chat function (post request with params, which includes apiToken + message)
-Tested and passed a run-through of chat send, display, and refresh functions.