I installed the edge offset addon from a saved file and enabled it in Blender 2.79, but it doesn’t show up. I’ve used it on previous versions of Blender with no problems and currently have 2.78B on my notebook. There was a note of some issue with 2.79 on the GitHub site, but I could find no further information.
Below you will see the mesh edges menu for 2.79 with no offset edges and a section of the addon list in the User Preferences that shows offset edges enabled. I’ve also included the mesh edges menu from Blender 2.78B which does show the offset edges options. Both systems are running Win 7 Pro SP1. The version of the Python script is 026.