w.r.t #31; Math.DivRem does not appear to be used for optimization purposes; the IL is just div + rem, appears to be an old issue http://stackoverflow.com/q/447282/80572
next bit of #31; smaller data type *does* lead to a very small but consistent improvement; commiting now for future reference, but this option is going away; supercedes existing CustomInt code
convert other CustomWrite<NumberType>'s to use smaller datatypes when possible; closes #31
reproduced speed gains from #36; implementing and adding a speedprooftest for it; closes #36