Add gitattributes file

Sets dat and spp files eol=crlf, this will hopefully fix the EOL problem
when creating zips (Windows not recognizing line endings).

.gitattributes

@@ -0,0 +1,11 @@
+# Set the default behavior, in case people don't have core.autocrlf set.
+* text=auto
+
+# Declare files that will always have CRLF line endings on checkout.
+*.spp text eol=crlf
+*.dat text eol=crlf
+*.txt text eol=crlf
+
+# Denote all files that are truly binary and should not be modified.
+*.png binary
+*.jpg binary