catch missing chrom exceptions for BigWig lookups
Merge branch 'master' of github.com:arq5x/gemini
Skip variants with the FILTER flag set on loading.

Most of the built in tools don't seem to use this flag, but should.
It also requires the user to use it every time they want to do a query.
This change makes GEMINI more conceptually a database of all of
the possible real variants.
Revert "Skip variants with the FILTER flag set on loading."

This reverts commit 29ec301f0c8167802ecb5889b658db67bba56bb9.