ls: moved generic URI utilities to uri.c

"ls" is a bad name for a library which parses URIs.  We'll move the
rest of the "ls" library later.

src/decoder_thread.c

@@ -30,7 +30,7 @@
 #include "mapper.h"
 #include "path.h"
 #include "log.h"
-#include "ls.h"
+#include "uri.h"
 
 #include <glib.h>