Relocate source files to an src/ subdirectory

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugins/tty.c

@@ -29,10 +29,10 @@
 #include <sys/stat.h>
 #include <lite/lite.h>
 
-#include "../finit.h"
-#include "../helpers.h"
-#include "../plugin.h"
-#include "../tty.h"
+#include "finit.h"
+#include "helpers.h"
+#include "plugin.h"
+#include "tty.h"
 
 static void watcher(void *arg, int fd, int events);