Make all text files under code/ directories go directly into git

.gitattributes

@@ -4,3 +4,4 @@ config* annex.largefiles=nothing
 
 * annex.backend=MD5E
 **/.git* annex.largefiles=nothing
+**/code/* annex.largefiles=((mimeencoding=binary)and(largerthan=0))