Add ability to read bw files and return maximum value across an interval

[donaldcampbelljr]

• created simple wrapper around BigTools BigWigRead::open_file(bigwigpath)?
  • might be unnecessary but thought it might be appreciated for making python bindings
• created func to give max value over an interval given a chromosome name (to be used downstream in geniml)
• added test to show it in action

[donaldcampbelljr]

• Needs python bindings

[nleroy917]

Returning an error instead of panicing would be helpful otherwise this looks great.

[nleroy917]

Sweet!

[nleroy917]

I'll add python bindings and push here in a second

[nleroy917]

@donaldcampbelljr I got the bindings in! Usage, then a couple notes:

import gtars

coverage = gtars.utils.read_big_wig_to_coverage("tests/data/test_all_core.bw")
val = coverage.stats("chr1", 0, 29, stat_type="max")

assert val == 4.0 # True

I have two notes on this:
I tried to keep it all as similar to what is there already, however:

1. I changed the API to be stat_type instead of type since the latter is a reserved keyword in Rust, and
2. To make the pyo3 bindings happy, I am doing something odd with the PyCoverage class... I simply store the file path in a string and then open it when I need to read a value. This way all the bigtools stuff stays in Rust and isn't exposed to python. This made it all super simple to write. Does this seem ok? Take a look at the commit, I am only slightly concerned with opening file over and over again.

[donaldcampbelljr]

This PR is probably no longer necessary since the bigtools python bindings may be sufficient. We can close this once confirmed.

[nleroy917]

I agree, we can close this