* Switching from Difference between dates to Add or subtract dates ignores the first date field
https://github.com/microsoft/calculator/issues/254
Date field needs to persist across Date Difference and Add/Subtract From Date Mode.
* Update DateCalculator.xaml.cpp
Addressing review comments (white space, small code refactor), also found a null pointer exception during testing, this fix addresses that as well.
* Issue 935 - Updates to Scientific/Graphing Keypad
Update Scientific and Graphing keyboard layouts to expose square root button at the top level
* Updated ScientificModeFunctionalTests/SmokeTest_Cube()
Updated broken test to work with changes.