Update configuration.rst for ...

Description of paired variant calling
Scaling improvements: avoid using uncompressed BAMs in pipelines which breaks sambamba on large files (#445). Provide better checks for zlib compressed ipython messages to avoid errors on truncated results
Merge pull request #443 from mjafin/master

FreeBayes: Reject non-somatic mutations in FILTER field
Merge pull request #444 from mjafin/patch-4

Update configuration.rst for ...