* Hack up support for gtkdoc-scangobj and use it in CMakeLists.txt.
* Trash gtkdoc-mktmpl, we won't need it.
* Always remove SGML/XML/HTML directories before filling them.
* Do not require gtk-doc to be installed.
* Use FindPackageHandleStandardArgs in FindGtkDoc.cmake.
* Fix installation (wrong source path).
* Don't install neither the documentation nor the desktop file on Windows.