Added a development note.

src/tirl/interpolators/fslinterpolator.py

@@ -16,6 +16,15 @@
 # SHBASECOPYRIGHT
 
 
+# DEVELOPMENT NOTES
+
+"""
+This interpolator does not handle the fill_value parameter. A fill_value of
+0 is hard-coded in the C++ implementation.
+
+"""
+
+
 # DEPENDENCIES
 
 import numpy as np