added sequence, coding sequence, and UTR properties to Transcript objects



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So if we have:

4th (base1) = beginning of start codon
10th (base1) = last element of stop codon

Then:

[:4] = 0, 1, 2, 3
[4:10] = 4, 5, 6, 7, 8, 9
[10:] = 10, 11

That won't include the 4th (1-base) element in the coding sequence, which starts at the 5th (1-base) element. Is that right? Do we not want to include the first element of the start codon? Is my math off?