Function to Multiply Factors

Gave the nutrition calculator the ability to multiply a base energy need
value by a factor (stress/activity)
Input check, Factor Popup

Input values are now checked to be numeric before starting calculators.
A popup has been added that will handle multiplying a base mifflin value
by activity/stress factors.
Factor Button, Factor Popup

Added a button to bring up the factor popup.
Factor popup contains two spinners for each type of factor and
automatically applies the factor when one is selected by the user.