Stage 3 proposal for issue #36 "Remove deprecated items"

<!ENTITY % basic.ph
              "%boolean; |
               %cite; |
               %keyword; |
               %ph; |
               %q; |
               %term; |
               %text; |
               %tm; |
               %xref; |
               %state;"
>
...
<!ENTITY % basic.ph.noxref.nocite
              "%boolean; |
               %keyword; |
               %ph; |
               %q; |
               %term; |
               %text; |
               %tm; |
               %state;"
>
...
<!ENTITY % basic.ph.notm
              "%boolean; |
               %cite; |
               %keyword; |
               %ph; |
               %q; |
               %term; |
               %text; |
               %xref; |
               %state;"
>

<!--                    LONG NAME: Boolean  (deprecated)           -->
<!ENTITY % boolean.content
                       "EMPTY"
>
<!ENTITY % boolean.attributes
              "state
                          (no |
                           yes |
                           -dita-use-conref-target)
                                    #REQUIRED
               %univ-atts;
               outputclass
                          CDATA
                                    #IMPLIED"
>
<!ELEMENT  boolean %boolean.content;>
<!ATTLIST  boolean %boolean.attributes;>

...
<!ATTLIST  boolean      %global-atts;  class CDATA "- topic/boolean "    >