automatic weights feature seems to be broken I don't recall since which version of Blender but I've noticed that literally all my character models and armatures no longer work with automatic bone weights feature. None. Every single time get this error:


  Bone Heat Weighting: failed to find solution for one or more bones


Actually, Blender fails to find solution for any of the bones.

Here's an example blend with a simplified armature and mesh to be parented to the armature ready. Try it yourself:
http://www.pasteall.org/blend/42650

Maybe I'm doing something wrong, but Blender didn't complain few versions back. What might be the issue?
One of the requirements for automatic bone weighting is to have a single mesh; your is made of many separate parts. I selected the main (body) vertices, then inverted the selection, hid the selected spare parts, then the auto weight went allright. Then you will have to manually weight the spare parts (or join them with the main mesh, manifold and unbroken). Auto weighting is an useful shortcut, but we cannot ask it for the complete job.