Added new status elements

1) A colored bar for showing the signal strength
2) Text field for displaying the text statuses
Better way to show device statuses

Instead of showing a popup to display the status of the device, I added
a text field next to the "Check Connection" button that will now
display it.

I also get rid of the "Powered on/off" part of the statuses.
Now has 3 options for range + a way to get signal strength

For the range, I added a third option, Not Detectable.
So now:
0 = Out of Range, 1 = In Range, and 2 = Not Detectable

I changed isInRange to getRange because it fit better with the argument
I added, which is a way to get the RSSI to use in the Signal Bar, and
it still makes sense.

Also, I made the code a bit more unifirm with the rest :)
New Signal Bar/Status Area + stepper for timerInterval

* Added the Signal Bar above the "Required Signal Strength" and slider.
* Added Status Area next to "Check Connectivity"
* Made the progressIndicator hide when not in use
* Widened the slider to size of Signal Bar and got rid of "bad" and
"good" text on the edges b/c the Signal Bar pretty much explains that
* Gave the timerInterval input a stepper with max value 99999 and a
NSNumberFormatter - no decimals/commas, just numbers