sources:
  
  calibre-1.3.0.tar.xz: c6acea5a8c9b045d01ba690ac8755de0028852d6
  calibre-1.5.0.tar.xz: 47edc5d5151cb01d79e1288435a40f505a46edd6
  calibre-1.7.0.tar.xz: 0553ad863f9b01bc424064d7a70c00aa363577df