lua: implement "luaclient".

This allows for starting Lua scripts in neutrino context from the
command line. Experimental, not fully regression-tested.

src/neutrino.h

@@ -34,6 +34,7 @@
 #define __neutrino__
 
 #include <configfile.h>
+#include <semaphore.h>
 
 #include <neutrinoMessages.h>
 #include "driver/framebuffer.h"
@@ -172,6 +173,9 @@ public:
 	CChannelList			*RADIOchannelList;
 	CChannelList			*channelList;
 
+	sem_t				lua_may_run;
+	sem_t				lua_did_run;
+
 	static CNeutrinoApp* getInstance();
 
 	void channelsInit(bool bOnly = false);