[bdg-formats-25] Added the oldPosition and oldCigar fields to the bdg.avdl schema.
 These correspond to the OP and OC fields in the SAM format.
 Addresses issue #25 in the bdg-formats project.
Merge pull request #34 from 'niranjan93/NK_schema_tags'

[bdg-formats-25] Added the oldPosition and oldCigar fields to the bdg.avdl schema.