fix issue #102 - 'make clean' cannot work

rebar.config

@@ -2,7 +2,9 @@
 %% ex: ts=4 sw=4 ft=erlang et
 
 {require_min_otp_vsn, "R17"}.
+{cover_enabled, true}.
 
+%% fail_on_warning, 
 {erl_opts, [debug_info, {parse_transform, lager_transform}]}.
 
 {erl_opts, [warn_export_all,
@@ -19,9 +21,8 @@
 
 {sub_dirs, [
     "rel",
-    "apps/emqtt",
-    "apps/emqttd",
-    "plugins/emqttd_plugin_demo"]}.
+    "apps/*/",
+    "plugins/*/"]}.
 
 {deps, [
 	{gproc, "0.4.*", {git, "git://github.com/uwiger/gproc.git", {branch, "master"}}},
@@ -29,3 +30,5 @@
 	{esockd, "2.*", {git, "git://github.com/emqtt/esockd.git", {branch, "master"}}},
 	{mochiweb, ".*", {git, "git://github.com/emqtt/mochiweb.git", {branch, "master"}}}
 ]}.
+
+{recursive_cmds, [ct, eunit, clean]}.