GridView: Implement old functions

[chynu]

Currently commented out functions in gridview.js:

• pollBotNames()
• displayOccupancyMatrix(height, width, size)
• Background image loading (under main())

[yangdanny97]

To provide a little bit of detail/clarification:

• pollBotNames may or may not be needed for selecting which bot to control in the controls panel, not sure if that dropdown is fully implemented @leotrj
• are we keeping the occupancy matrix stuff?
• I'll take a look at background image loading once we get more important functionality done

[chynu]

Thanks for the clarifications - we can discuss this at our next meeting / on slack.