Added exit & default to help if no main is specified

src/cligen/command_node.cr

@@ -187,6 +187,7 @@ module CliGen
             {% for cls in CliGen::Command.subclasses %}
           when CliGen::CommandNode({{cls.name}})
             match.as(CommandNode({{cls}})).process(args.reject(&.processed?))
+            exit 0
             {% end %}
           else
             raise "ERROR : Couldn't find thing"
@@ -259,12 +260,16 @@ module CliGen
           {% if T.has_method?(:main) %}
             cls.main
           {% else %}
-            abort help
+            puts help
-            #raise "ERROR : CommandNode({{T}})\#{{@def.name}} : No subcommand matched and no #main defined"
+            puts "ERROR : CommandNode({{T}})\#{{@def.name}} : No subcommand matched and no #main defined"
           {% end %}
+            exit 0
         end
         {% end %}
       end
+      {% else %}
+        puts self.as(Nil).help
+        exit 0
       {% end %}
     end
   end