Controlling the output format

Deliverance can produce output as HTML or XHTML. On each request, it determines the output format by looking for DOCTYPE declarations in the theme and content. The precedence rules it uses are:

1. If the theme declares its doctype, it is used in the output always.
2. Otherwise, if the content declares a doctype, it is used in the output.
3. If neither document declares a doctype, the output format is HTML.

This allows the integrator to override the output format by specifying a doctype in the theme.