Denote gif as binary

Kevin Su · Kevin Su · commit d4d542c7ca31 · 2016-04-27T12:30:07.000-07:00
Ensure that git does not convert CRLF to LF in screenshot gifs on Linux and
OSX.
diff --git a/.gitattributes b/.gitattributes
@@ -1,2 +1,4 @@
 # Force text files to have unix eols, so Windows/Cygwin does not break them
 *.* eol=lf
+
+*.gif binary
