Fix to include ends of chromosomes.

[avantikalal]

Currently get_intervals.py deletes intervals that extend beyond the chromosome length. This means that the last few kilobases of each chromosome are not covered in the intervals and no prediction is made for them when we perform inference.
These bases should somehow be included.
Pad the h5 with zeros beyond the chromosome size, then at the time of writing the bedGraph file trim off the excess zeros.

[ntadimeti]

@avantikalal where is the chromosome length defined ? and how do we know the full length of the chromosome to know how many zeroes to append ?

[ntadimeti]

De-prioritizing this for v0.3.0