Changes in the UI

Here is the pull request again with all issues that we have discoused fixed.

Tickers values themselves will probably change, but we have the baseline in code for different values based if the axis are logritmic or linear.
I suspect the reason for convertToMmol is because the value was just set - suggesting that the value listed in the range is mgdl.

Is this safe if the user first enters the range as mmol but then goes back and changes the units to mmol? Perhaps we should also have a sanity check to make sure that the values are within the range that the device can actually read.

While on the topic of sanity checks - we should also have something that won't allow the user to set the low range higher than the high range.