Formatted tooltips and begun cell colour change

I formatted the temperature values outputted to the tooltips so that they read to one decimal place.

In addition, I tried various different methods of making the sensors change colour once the temperature levels got too high. I remembered using flag variables at uni with Fortran and so created a 'this.Flag' array which becomes 1 if the temperature is too high. However, I can't seem to get this array working in the 'renderRacks' function as it appears empty on the console log but is populated if I put a console log into one of the functions further down. I think it's another 'this' problem but it may be that the array is somehow reset to make it empty?