PNG files explicitly marked as binary (resolves #39)

.gitattributes

@@ -1,3 +1,16 @@
+# Set the default behavior
 * text=auto eol=lf
 *.{cmd,[cC][mM][dD]} text eol=crlf
 *.{bat,[bB][aA][tT]} text eol=crlf
+
+# Explicitly declare text files to always be normalized and converted to native line endings on checkout
+*.cpp text
+*.h text
+*.py text
+*.txt text
+*.md text
+*.yml text
+
+# Denote all files that are truly binary and should not be modified
+*.png binary
+*.jpg binary