text() now uses escapes for tabs & page-breaks

- using the \f escape for strings (or &break; entity for xml) will
cause subsequent characters to be moved to the next text-frame (or Text
in a paginate() sequence).
- the auto-indentation behavior of first-lines of paragraphs can be
overridden using \t (or &indent;) to force indentation and \b (or
&flush;) to force un-indentation.