HACKING,README,php/docs/index.rst: Make PHP 5.4 the minimum
officially supported version, as 5.3 has now reached EOL.

git-svn-id: file:///home/xapian-svn/xapian/trunk@18251 6b2f1b92-a4f3-0310-943f-de3cbe41748b
xapian-headers.i: Ignore new iterator API (which we see via friend
declarations).

git-svn-id: file:///home/xapian-svn/xapian/trunk@18252 6b2f1b92-a4f3-0310-943f-de3cbe41748b