Minor RFE: list latest commit in merge messages

[joshmoore]

Merged PRs:
  # PR 1969 melissalinkert 'ScreenReader: the next generation'
  # PR 1976 joshmoore 'Flex NPE'
  # PR 1990 simleo 'FileStitcher: call setId on all readers in ExternalSeries'
  # PR 1995 melissalinkert 'ScanR: return blank planes instead of skipping missing wells'
  # PR 2006 joshmoore 'Temporarily disable DeltavisionReader for IDR'

could benefit by having the short sha1s at the end:

  # PR 1969 melissalinkert 'ScreenReader: the next generation (3e3cbf9b)