Comply with dl repo + allow bed row index as variant index

[krrome]

Comply with dl repo:

• if the dataloader doesn't have any shape information of the generated inputs then derive them from the model object

allow bed row index as variant index:

• the index in the GenomicRanges object returned by the dataloader in the metadata field can now be the row index of the bed file. the link between the bed file row index and the variant in the vcf is stored in a gzipped temporary file.
• implemented for variant effect prediction and for mutation maps.

[krrome]

circleci tests fail because of a kipoi setup problem?!

[coveralls]

Pull Request Test Coverage Report for Build 126

• 57 of 62 (91.94%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 75.789%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kipoi_veff/utils/generic.py	10	15	66.67%
<!--	Total:	57	62	91.94%	-->

Totals
Change from base Build 117:	0.2%
Covered Lines:	2160
Relevant Lines:	2850

---

💛 - Coveralls