Add a timer for blood glucose check - not a reminder

[sanjeevdwivedi]

We should be able to set a timer after a meal to check the blood glucose level after a prespecified timer has expired. Essentially, different bodies work differently and different people have different objectives. Some want to test glucose level after 2 hours to see if it is back to normal and some want to test it when it has hit peak after eating - between 45-75 minutes after eating. This timer should be customizable.

The user should simply have a button saying "start timer" and when it expires, we hear a chime so that we know that it is time to test the blood glucose level.