Doxygen: enable non-implicit favicons.

Doxyfile-mcss

@@ -96,6 +96,8 @@ M_PAGE_FINE_PRINT = "<p>Magnum docs. Part of the <a href="http://magnum.graphics
 
 M_SEARCH_HELP = "Search for symbols, directories, files, pages, OpenGL/GLSL and OpenAL APIs. You can omit any prefix from the symbol or file path; adding a <code>:</code> or <code>/</code> suffix lists all members of given symbol or directory. Navigate through the list using <span class="m-label m-dim">&darr;</span> and <span class="m-label m-dim">&uarr;</span>, press <span class="m-label m-dim">Enter</span> to go."
 
+M_FAVICON = doc/favicon.ico
+
 M_LINKS_NAVBAR1 = \
     "getting-started building cmake" \
     "pages features platforms example-index tips utilities"

Doxyfile-public

@@ -96,4 +96,6 @@ M_SEARCH_DOWNLOAD_BINARY = YES
 
 M_SEARCH_EXTERNAL_URL = "https://google.com/search?q=site:doc.magnum.graphics+Magnum+{query}"
 
+M_FAVICON = http://doc.magnum.graphics/favicon.ico
+
 # kate: hl Doxyfile