Added git_diff_stats test files

tests/resources/diff_format_email/.gitted/HEAD

+ref: refs/heads/master

tests/resources/diff_format_email/.gitted/config

+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = false
+	logallrefupdates = true
+	ignorecase = true
+	precomposeunicode = true

tests/resources/diff_format_email/.gitted/info/exclude

+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~

tests/resources/diff_format_email/.gitted/refs/heads/binary

+a3ac918e3a6604294b239cb956363e83d71abb3b

tests/resources/diff_format_email/.gitted/refs/heads/master

+873806f6f27e631eb0b23e4b56bea2bfac14a373

tests/resources/diff_format_email/.gitted/refs/heads/multihunk

+cd471f0d8770371e1bc78bcbb38db4c7e4106bd2

tests/resources/diff_format_email/.gitted/refs/heads/rename

+4ca10087e696d2ba78d07b146a118e9a7096ed4f

tests/resources/diff_format_email/file1.txt.renamed

+file1.txt
+file1.txt
+_file1.txt_
+file1.txt
+file1.txt
+file1.txt_renamed
+file1.txt
+
+
+file1.txt
+file1.txt
+file1.txt_renamed
+file1.txt
+file1.txt
+_file1.txt_
+_file1.txt_
+file1.txt

tests/resources/diff_format_email/file2.txt

+file2
+file2
+file2
+file2!
+file2

tests/resources/diff_format_email/file3.txt

+file3
+file3!
+file3
+file3
+file3