Add .gitattributes file with Git core.autorclf settings

Author: drmfinlay

.gitattributes

@@ -0,0 +1,9 @@
+# Set the default behavior, in case people don't have core.autocrlf set.
+* text=auto
+
+# Explicitly declare text files you want to always be normalized and converted
+# to native line endings on checkout.
+*.py text
+*.txt text
+*.rst text
+*.md text