Add a tool for creating smooth streaming manifests

It can also optionally split the file into individual fragments,
which allows it to be served from any web server without any
server side support.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/Makefile

@@ -354,6 +354,6 @@ SKIPHEADERS-$(CONFIG_NETWORK)            += network.h rtsp.h
 
 EXAMPLES  = metadata output
 TESTPROGS = seek
-TOOLS     = aviocat pktdumper probetest
+TOOLS     = aviocat ismindex pktdumper probetest
 
 $(SUBDIR)output-example$(EXESUF): ELIBS = -lswscale