middleman/middleman — pull request #1348 by fredkelly (2014-08-13 22:47:19+00:00)
Title: Allow setting of imagesdir from asciidoc_attributes

I wanted to be able to set `imagesdir=` myself, the current code will overwrite the user provided setting no matter what. This PR adds a check to only set the default path if one has not been provided via `asciidoc_attributes`.