Add the blowfish encryption patch from Mohsin Ahmed. Needs more work.

runtime/doc/editing.txt

@@ -1361,6 +1361,11 @@ the file is encrypted.
 To disable the encryption, reset the 'key' option to an empty value: >
 	:set key=
 
+You can use the 'cryptmethod' option to select the type of encryption.  Do
+this before writing the file.  When reading an encrypted file it will be set
+automatically to the method used when that file was written.  You can change
+'cryptmethod' before writing that file to change the method.
+
 When reading a file that has been encrypted and this option is not empty, it
 will be used for decryption.  If the value is empty, you will be prompted to
 enter the key.  If you don't enter a key, the file is edited without being