Added buildsystem for apps. Doesn't honor dependencies yet (changing a grc file won't cause generating new py file).
diff --git a/apps/airprobe_usrp.grc b/apps/airprobe_usrp.grc
index 82f0109..4fa8c2a 100644
--- a/apps/airprobe_usrp.grc
+++ b/apps/airprobe_usrp.grc
@@ -6,7 +6,7 @@
     <key>options</key>
     <param>
       <key>id</key>
-      <value>gsm_receiver_usrp</value>
+      <value>airprobe_usrp</value>
     </param>
     <param>
       <key>_enabled</key>