All files in must be stored as UTF-8 character encoding. In general most files that do not contain accented characters should use the 7 bit ASCII representation, which is a valid subset of UTF-8.
There should be no whitespace before the first <?php tag. Closing ?> tags should be omitted.
Files must have lines ending in LineFeed (0x0A) characters when stored in the CVS. This is normally handled automatically by the client, but some clients (especially on Windows) do not automatically convert.