Fixed trait distribution roundoff error for last variation

If 3 variations are added (33.33%) each, they were rounded to 33% each.
Fixed so that the last variation will have 100-totalSoFar i.e. 34%
DeltaTickModelReader update #2

* Plot and Quantity blocks should work (with traits).
* Minor change to getTrait interface of QuantityBlock
* DiveIn block NOT SUPPORTED YET.