This macro provides the capability of the out of the box standard_header
and standard_footer. The macro's name is 'master'; it defines just one
slot to be filled (main). An example template that uses this macro can be
found in SimpleWelcome.
<html xmlns:tal="http://xml.zope.org/namespaces/tal"
xmlns:metal="http://xml.zope.org/namespaces/metal"
metal:define-macro="master">
<head>
<title tal:content="here/title">The title</title>
</head>
<body bgcolor="#999999">
<div metal:define-slot="main">
If you supply a tag with a 'fill-slot="main"' attribute
when using this macro, that tag will replace this text.
</div>
<p tal:content="structure here/ZopeAttributionButton"></p>