Improved documentation via doxygen

Signed-off-by: Tobias Frisch <tfrisch@uni-koblenz.de>

Doxyfile

@@ -1545,7 +1545,7 @@ DISABLE_INDEX          = NO
 # The default value is: NO.
 # This tag requires that the tag GENERATE_HTML is set to YES.
 
-GENERATE_TREEVIEW      = NO
+GENERATE_TREEVIEW      = YES
 
 # The ENUM_VALUES_PER_LINE tag can be used to set the number of enum values that
 # doxygen will group on one line in the generated HTML documentation.
@@ -2299,7 +2299,7 @@ EXTERNAL_PAGES         = YES
 # powerful graphs.
 # The default value is: YES.
 
-CLASS_DIAGRAMS         = YES
+CLASS_DIAGRAMS         = NO
 
 # You can include diagrams made with dia in doxygen documentation. Doxygen will
 # then run dia to produce the diagram and insert it in the documentation. The
@@ -2321,7 +2321,7 @@ HIDE_UNDOC_RELATIONS   = YES
 # set to NO
 # The default value is: NO.
 
-HAVE_DOT               = NO
+HAVE_DOT               = YES
 
 # The DOT_NUM_THREADS specifies the number of dot invocations doxygen is allowed
 # to run in parallel. When set to 0 doxygen will base this on the number of
@@ -2460,7 +2460,7 @@ INCLUDED_BY_GRAPH      = YES
 # The default value is: NO.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-CALL_GRAPH             = NO
+CALL_GRAPH             = YES
 
 # If the CALLER_GRAPH tag is set to YES then doxygen will generate a caller
 # dependency graph for every global function or class method.
@@ -2472,7 +2472,7 @@ CALL_GRAPH             = NO
 # The default value is: NO.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-CALLER_GRAPH           = NO
+CALLER_GRAPH           = YES
 
 # If the GRAPHICAL_HIERARCHY tag is set to YES then doxygen will graphical
 # hierarchy of all classes instead of a textual one.