Move code for root back to Spectator#describe

There seems to be a problem using def in block.
This broke helper methods and gives the error: `can't declare def 
dynamically`.

src/spectator.cr

@@ -5,7 +5,11 @@ module Spectator
   VERSION = "0.1.0"
 
   macro describe(what, &block)
-    DSL.root({{what}}) {{block}}
+    module SpectatorExamples
+      include ::Spectator::DSL::StructureDSL
+
+      describe({{what}}) {{block}}
+    end
   end
 
   at_exit do

src/spectator/dsl.cr

@@ -2,12 +2,5 @@ require "./dsl/*"
 
 module Spectator
   module DSL
-    macro root(what, &block)
-      module SpectatorExamples
-        include StructureDSL
-        
-        describe({{what}}) {{block}}
-      end
-    end
   end
 end