Adjusted helium-3 generation

Changed depositHelium3 method to add no more than 1,000 3He for each
pass at a Cell.
Decreased amount of 3He deposited at each hotspot from 10,000 to 3,000
Increased number of hotspots from 3–6 to 7–10.
Added diagnostic line to NewFrame's paint method that prints the Grid to
the console.