Added getBoundedHelium3Amount method

For use with the GUI.
Added depositHelium3 method to Grid class
Fixed helium-3 rendering color out of bounds bug

Changed getHelium3Amount calls in NewFrame class to instead call
getBoundedHelium3Amount.  Fixes #2.
Fixed depositHelium3 method infinite loop problem.
Changed generateHelium3 method to utilize depositHelium3 method.