Add generated grgsm_livemon_headless from grgsm_livemon_headless.grc and install the program.
diff --git a/apps/CMakeLists.txt b/apps/CMakeLists.txt
index 09e7257..2d29446 100644
--- a/apps/CMakeLists.txt
+++ b/apps/CMakeLists.txt
@@ -23,6 +23,7 @@
 GR_PYTHON_INSTALL(
     PROGRAMS
     grgsm_livemon
+    grgsm_livemon_headless
     grgsm_scanner
     grgsm_decode
     DESTINATION bin