add a message of `describe' to description of tap's output

## before
not ok 1 - has one window: FAILED

## after
not ok 1 - Application 'test' has one window: FAILED

lib/motion/spec.rb

@@ -175,12 +175,18 @@ module Bacon
 
   module TapOutput
     @@count = 1
+    @@describe = ""
 
-    def handle_specification_begin(name); end
-    def handle_specification_end        ; end
+    def handle_specification_begin(name)
+      @@describe << "#{name} "
+    end
+
+    def handle_specification_end
+      @@describe = ""
+    end
 
     def handle_requirement_begin(description)
-      @description = description
+      @description = @@describe + description
       ErrorLog.replace ""
     end