Upgrade Doxyfile for the latest Doxygen.

Author: sadiepowell

docs/Doxyfile

@@ -37,6 +37,7 @@ MARKDOWN_SUPPORT       = YES
 TOC_INCLUDE_HEADINGS   = 5
 MARKDOWN_ID_STYLE      = GITHUB
 AUTOLINK_SUPPORT       = YES
+AUTOLINK_IGNORE_WORDS  =
 BUILTIN_STL_SUPPORT    = YES
 CPP_CLI_SUPPORT        = NO
 SIP_SUPPORT            = NO
@@ -61,6 +62,7 @@ EXTRACT_ANON_NSPACES   = NO
 RESOLVE_UNNAMED_PARAMS = YES
 HIDE_UNDOC_MEMBERS     = NO
 HIDE_UNDOC_CLASSES     = NO
+HIDE_UNDOC_NAMESPACES  = YES
 HIDE_FRIEND_COMPOUNDS  = NO
 HIDE_IN_BODY_DOCS      = NO
 INTERNAL_DOCS          = NO
@@ -90,13 +92,15 @@ SHOW_NAMESPACES        = YES
 FILE_VERSION_FILTER    =
 LAYOUT_FILE            =
 CITE_BIB_FILES         =
+EXTERNAL_TOOL_PATH     =
 QUIET                  = NO
 WARNINGS               = NO
 WARN_IF_UNDOCUMENTED   = NO
 WARN_IF_DOC_ERROR      = YES
 WARN_IF_INCOMPLETE_DOC = YES
 WARN_NO_PARAMDOC       = NO
 WARN_IF_UNDOC_ENUM_VAL = NO
+WARN_LAYOUT_FILE       = YES
 WARN_AS_ERROR          = NO
 WARN_FORMAT            = "$file:$line: $text"
 WARN_LINE_FORMAT       = "at line $line of file $file"
@@ -121,6 +125,7 @@ FILTER_PATTERNS        =
 FILTER_SOURCE_FILES    = NO
 FILTER_SOURCE_PATTERNS =
 USE_MDFILE_AS_MAINPAGE = README.md
+IMPLICIT_DIR_DOCS      = YES
 FORTRAN_COMMENT_AFTER  = 72
 SOURCE_BROWSER         = NO
 INLINE_SOURCES         = NO
@@ -179,6 +184,7 @@ DISABLE_INDEX          = NO
 GENERATE_TREEVIEW      = NO
 FULL_SIDEBAR           = NO
 ENUM_VALUES_PER_LINE   = 4
+SHOW_ENUM_VALUES       = NO
 TREEVIEW_WIDTH         = 250
 EXT_LINKS_IN_WINDOW    = NO
 OBFUSCATE_EMAILS       = YES
@@ -289,6 +295,7 @@ DIAFILE_DIRS           =
 PLANTUML_JAR_PATH      =
 PLANTUML_CFG_FILE      =
 PLANTUML_INCLUDE_PATH  =
+PLANTUMLFILE_DIRS      =
 DOT_GRAPH_MAX_NODES    = 50
 MAX_DOT_GRAPH_DEPTH    = 0
 DOT_MULTI_TARGETS      = NO