add: List of contributors [AUTHORS]

AUTHORS.txt

@@ -0,0 +1,33 @@
+Software Development
+--------------------
+
+- `Andreas Schuh`_
+- `Daniel Rueckert`_
+- `Julia Schnabel`_
+
+
+Contributors
+------------
+
+- Wenzhe Shi
+
+  - *Helped to reimplement and test his sparse free-form deformation in the Registration module.*
+
+- Stefan Pszczolkowski Parraguez
+
+  - *Implemented the image gradient similarity measures of the Registration module.*
+  - *Added statistical free-form deformation class to the Transformation module.*
+
+- Ghislain Antony Vaillant
+
+  - *Reimplemented the transformation inversion code using Boost instead of GSL.*
+
+Advisors
+--------
+
+- `Daniel Rueckert`_
+
+
+.. _Daniel Rueckert: http://www.imperial.ac.uk/people/d.rueckert
+.. _Julia Schnabel:  http://www.imagingcdt.com/about/cdt-management/professor-julia-schnabel
+.. _Andreas Schuh:   http://www.andreasschuh.com/