Urgency

- Added a coefficient for ageing which is the increase (or decrease)
   of urgency per day. The calculated urgency offset due to ageing
   can be limited by setting urgency.age.max.

src/commands/CmdShow.cpp

@@ -196,6 +196,8 @@ int CmdShow::execute (std::string& output)
     " urgency.project.coefficient"
     " urgency.tags.coefficient"
     " urgency.waiting.coefficient"
+    " urgency.age.coefficient"
+    " urgency.age.max"
     " verbose"
     " weekstart"
     " xterm.title"