Update parallel.rst

Fix typos
Galaxy tool configuration for single sample bcbio variant calling. Thanks to @jmchilton for advice
Update cancer test data to use ICGC-TCGA mutation calling challenge data on chr22 that includes indels #428
Merge pull request #431 from mjafin/patch-3

Update parallel.rst for SGE config
Enable de-duplication for pre-aligned inputs using biobambam. Thanks to Severine Catreux