Upgrade the Doxygen config file with "doxygen -u".

docs/Doxyfile

@@ -7,6 +7,7 @@ OUTPUT_DIRECTORY       = docs/doxygen
 CREATE_SUBDIRS         = NO
 ALLOW_UNICODE_NAMES    = NO
 OUTPUT_LANGUAGE        = English
+OUTPUT_TEXT_DIRECTION  = None
 BRIEF_MEMBER_DESC      = YES
 REPEAT_BRIEF           = YES
 ABBREVIATE_BRIEF       =
@@ -17,6 +18,7 @@ STRIP_FROM_PATH        =
 STRIP_FROM_INC_PATH    =
 SHORT_NAMES            = NO
 JAVADOC_AUTOBRIEF      = NO
+JAVADOC_BANNER         = NO
 QT_AUTOBRIEF           = NO
 MULTILINE_CPP_IS_BRIEF = NO
 INHERIT_DOCS           = YES
@@ -28,14 +30,17 @@ OPTIMIZE_OUTPUT_FOR_C  = NO
 OPTIMIZE_OUTPUT_JAVA   = NO
 OPTIMIZE_FOR_FORTRAN   = NO
 OPTIMIZE_OUTPUT_VHDL   = NO
+OPTIMIZE_OUTPUT_SLICE  = NO
 EXTENSION_MAPPING      =
 MARKDOWN_SUPPORT       = YES
+TOC_INCLUDE_HEADINGS   = 5
 AUTOLINK_SUPPORT       = YES
 BUILTIN_STL_SUPPORT    = YES
 CPP_CLI_SUPPORT        = NO
 SIP_SUPPORT            = NO
 IDL_PROPERTY_SUPPORT   = YES
 DISTRIBUTE_GROUP_DOC   = NO
+GROUP_NESTED_COMPOUNDS = NO
 SUBGROUPING            = YES
 INLINE_GROUPED_CLASSES = NO
 INLINE_SIMPLE_STRUCTS  = NO
@@ -43,6 +48,7 @@ TYPEDEF_HIDES_STRUCT   = NO
 LOOKUP_CACHE_SIZE      = 0
 EXTRACT_ALL            = NO
 EXTRACT_PRIVATE        = NO
+EXTRACT_PRIV_VIRTUAL   = NO
 EXTRACT_PACKAGE        = NO
 EXTRACT_STATIC         = NO
 EXTRACT_LOCAL_CLASSES  = YES
@@ -83,6 +89,7 @@ WARNINGS               = NO
 WARN_IF_UNDOCUMENTED   = NO
 WARN_IF_DOC_ERROR      = YES
 WARN_NO_PARAMDOC       = NO
+WARN_AS_ERROR          = NO
 WARN_FORMAT            = "$file:$line: $text"
 WARN_LOGFILE           =
 INPUT                  =
@@ -130,6 +137,7 @@ HTML_COLORSTYLE_HUE    = 220
 HTML_COLORSTYLE_SAT    = 100
 HTML_COLORSTYLE_GAMMA  = 80
 HTML_TIMESTAMP         = NO
+HTML_DYNAMIC_MENUS     = YES
 HTML_DYNAMIC_SECTIONS  = NO
 HTML_INDEX_NUM_ENTRIES = 100
 GENERATE_DOCSET        = YES
@@ -177,6 +185,7 @@ GENERATE_LATEX         = NO
 LATEX_OUTPUT           = latex
 LATEX_CMD_NAME         = latex
 MAKEINDEX_CMD_NAME     = makeindex
+LATEX_MAKEINDEX_CMD    = makeindex
 COMPACT_LATEX          = NO
 PAPER_TYPE             = a4
 EXTRA_PACKAGES         =
@@ -190,6 +199,8 @@ LATEX_BATCHMODE        = NO
 LATEX_HIDE_INDICES     = NO
 LATEX_SOURCE_CODE      = NO
 LATEX_BIB_STYLE        = plain
+LATEX_TIMESTAMP        = NO
+LATEX_EMOJI_DIRECTORY  =
 GENERATE_RTF           = NO
 RTF_OUTPUT             = rtf
 COMPACT_RTF            = NO
@@ -205,6 +216,7 @@ MAN_LINKS              = NO
 GENERATE_XML           = NO
 XML_OUTPUT             = xml
 XML_PROGRAMLISTING     = YES
+XML_NS_MEMB_FILE_SCOPE = NO
 GENERATE_DOCBOOK       = NO
 DOCBOOK_OUTPUT         = docbook
 DOCBOOK_PROGRAMLISTING = NO
@@ -228,9 +240,7 @@ GENERATE_TAGFILE       =
 ALLEXTERNALS           = NO
 EXTERNAL_GROUPS        = YES
 EXTERNAL_PAGES         = YES
-PERL_PATH              = /usr/bin/perl
 CLASS_DIAGRAMS         = YES
-MSCGEN_PATH            =
 DIA_PATH               =
 HIDE_UNDOC_RELATIONS   = YES
 HAVE_DOT               = NO
@@ -257,6 +267,7 @@ DOTFILE_DIRS           =
 MSCFILE_DIRS           =
 DIAFILE_DIRS           =
 PLANTUML_JAR_PATH      =
+PLANTUML_CFG_FILE      =
 PLANTUML_INCLUDE_PATH  =
 DOT_GRAPH_MAX_NODES    = 50
 MAX_DOT_GRAPH_DEPTH    = 0