Safeguard to fahrenheit conversion

Passed fahrenheight value is converted to decimal to safeguard against valueerror.
Removed erroneous function.
Changeable Temps, Text Size

Added a spinner to select fahrenheit/celcius for pennstate.
Decrease font size of equation title for better fit.
Temp Units, Popup Title

Added section to convert temperature to celcius if entered in fahrenheit.
Output popup title now displays the active equation.