Use interactive svg for doxygen graphs

Doxyfile

@@ -2205,7 +2205,7 @@ DIRECTORY_GRAPH        = YES
 # The default value is: png.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_IMAGE_FORMAT       = png
+DOT_IMAGE_FORMAT       = svg
 
 # If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
 # enable generation of interactive SVG images that allow zooming and panning.
@@ -2217,7 +2217,7 @@ DOT_IMAGE_FORMAT       = png
 # The default value is: NO.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-INTERACTIVE_SVG        = NO
+INTERACTIVE_SVG        = YES
 
 # The DOT_PATH tag can be used to specify the path where the dot tool can be
 # found. If left blank, it is assumed the dot tool can be found in the path.