Make Trace numerically flat.

Author: kpeeters

core/properties/Trace.hh

@@ -5,10 +5,11 @@
 #include "properties/Symmetric.hh"
 #include "properties/Distributable.hh"
 #include "properties/IndexInherit.hh"
+#include "properties/NumericalFlat.hh"
 
 namespace cadabra {
 
-	class Trace : public Distributable, public IndexInherit, virtual public property {
+	class Trace : public Distributable, public IndexInherit, public NumericalFlat, virtual public property {
 		public:
 			Trace();
 			virtual std::string name() const override;

web2/cadabra2/source/changelog.html

@@ -19,7 +19,7 @@ <h1>Change log</h1>
 <h3>github master</h3>
 <ul>
   <li>More versatile handling of <tt>Trace</tt>, including sorting
-  using cyclic symmetry (Connor).></li>
+  using cyclic symmetry (Connor).</li>
   <li>Fixes for <tt>combine</tt> (Connor).</li>
   <li>Save command-line history (Connor).</li>
   <li>Make imported notebooks use the default <tt>post_process</tt> function.</li>