Off by 1 error on end position bounds check

[adamnovak]

I loaded up a graph with a 142 bp path in it. I asked to see that path from 1 to 142. I was told that that ran off the end of the 142 bp path, and I had to use 1-141 instead.

We should accept 1-based inclusive ranges that end on the last base of the path.

[adamnovak]

Really the problem is that vg chunk and BED both currently use 0-based coordinates, but we want the UI for the tube map to use 1-based coordinates like the genome browser.