A while ago, I made a plugin for designing papercraft patterns. It allows you to unfold models into flat patterns, add tabs, and export them as SVGs. Just recently, I finally got around to polishing it up and putting it online. I call it Flattery, and you can get it here.
NOTE the latest version available from the PluginStore works in >= v2014 AND also earlier versions...
It's got three main tools for designing patterns.
The Unfold tool unfolds models into flat patterns:
the Reunite Edges tool lets you adjust the layout of the patterns:
and the Add Tabs tool makes glue tabs:
It's also got an SVG export button so you can export your pattern to a program like Illustrator or Inkscape to color and print it.