doxygen: Several dependencies made optional.

Doxygen should be available without texlive and ghostscript.

doc-tools/doxygen/DEPENDS

@@ -1,10 +1,10 @@
-depends  bison
-depends  sed
-depends  flex
-depends  ghostscript
-depends  texlive
+depends bison
+depends flex
+depends sed
+depends perl
 
-optional_depends "perl"     ""  ""  "Buile perl interpreter support"
-optional_depends "qt4"      ""  ""  "Qt 4.x GUI support"
-optional_depends "Python"   ""  ""  "Build the doc files"
-optional_depends "graphviz" ""  ""  "Dot support"
+optional_depends "ghostscript" "" "" "Formulas support"
+optional_depends "graphviz" "" ""  "Graphs support"
+optional_depends "Python" "" "" "Build the doc files"
+optional_depends "qt4" "" "" "Build Doxywizard GUI"
+optional_depends "texlive" "" "" "LaTeX, Postscript and PDF output"