Optimize the SolveBio ClinVar query to prevent slow variant resource requests

Remove the by-gene filter to narrow down the result sets and return only the first 10 results from the query.
Adds the total result count to the clinvar dictionary in the variant resource. Also fixes an issue with the genomic position filter.

Signed-off-by: David Caplan <dcaplan@gmail.com>
Merge pull request #241 from solvebio/solvebio-speed

Optimize the SolveBio ClinVar query to prevent slow variant resource requests