Added the 3D reference shape and a readme explaining the files in share/

share/readme.txt

+eos: A lightweight header-only 3D Morphable Model fitting library in modern C++11/14
+=========
+
+Files in this directory:
+
+- ibug2did.txt:
+	Mappings from the popular IBUG 68-point 2D facial landmarks markup to
+	Surrey Face Model indices.
+
+- sfm_shape_3448.bin:
+	The public shape-only Surrey 3D Morphable Face Model.
+	To obtain a full 3DMM and higher resolution levels, follow the
+	instructions at <todo: add link to the page of the Uni>.
+	Details about the different models can be found in:
+	<todo: add publication>.
+
+- reference.obj:
+	The reference 3D shape used to built the model. We make it available so 
+	that new user-defined landmark points can be marked in this lowest-resolution
+	model, if the points exist here.