Added 'binary/octet-stream' as PDF mime. Fixes #1840 and #1828

Signed-off-by: Alex Bilbie <alex@alexbilbie.com>
diff --git a/application/config/mimes.php b/application/config/mimes.php
index 48771dc..af1c95f 100644
--- a/application/config/mimes.php
+++ b/application/config/mimes.php
@@ -49,7 +49,7 @@
 	'sea'	=>	'application/octet-stream',
 	'dll'	=>	'application/octet-stream',
 	'oda'	=>	'application/oda',
-	'pdf'	=>	array('application/pdf', 'application/x-download'),
+	'pdf'	=>	array('application/pdf', 'application/x-download', 'binary/octet-stream'),
 	'ai'	=>	'application/postscript',
 	'eps'	=>	'application/postscript',
 	'ps'	=>	'application/postscript',