Test improved organization of the doxygen documentation, using modules.

doc/doxygen/Doxyfile

@@ -1990,7 +1990,7 @@ MAN_LINKS              = NO
 # captures the structure of the code including all documentation.
 # The default value is: NO.
 
-GENERATE_XML           = YES
+GENERATE_XML           = NO
 
 # The XML_OUTPUT tag is used to specify where the XML pages will be put. If a
 # relative path is entered the value of OUTPUT_DIRECTORY will be put in front of

doc/doxygen/doxygen.css

@@ -127,8 +127,7 @@ span.legend {
   text-align: center; }
 
 span.arrow {
-  /* width: 32px; */
-  padding-left: 0px; }
+  width: 16px; }
 
 h3.version {
   font-size: 90%;
@@ -668,8 +667,8 @@ div.directory {
 .directory td.entry {
   white-space: nowrap;
   padding-right: 6px;
-  padding-top: 3px;
-  padding-bottom: 3px; }
+  padding-top: 2px;
+  padding-bottom: 2px; }
 
 .directory td.entry a {
   outline: none; }

doc/doxygen/doxygen.scss

@@ -205,8 +205,7 @@ span.legend {
 }
 
 span.arrow {
-    /* width: 32px; */
-    padding-left: 0px;
+    width: 16px;
 }
 
 h3.version {
@@ -963,8 +962,8 @@ div.directory {
 .directory td.entry {
     white-space: nowrap;
     padding-right: 6px;
-    padding-top: 3px;
-    padding-bottom: 3px;
+    padding-top: 2px;
+    padding-bottom: 2px;
 }
 
 .directory td.entry a {