Added new callback attach_dtx_file
C20 Implementation and tests of attach dtx file epp script
Merge pull request #91 from jbeast/picogreen_dtx_file_attachment

C20 Picogreen dtx file attachment
Changes to Pico DTX step

Will now pick up standard plate file too
Updated POD
Merge pull request #92 from jbeast/pico_green_fixes

Changes to Pico DTX step