[Cin]batchrender

Right now if you point batch render function from command line to non-xml file Cin will chew first, fail later. I added check hopefully preventing this from happening at least on non-xml files (you can still shoot your xml file with this gun)

I'm not sure if I understand what to do. I'm getting these results: Without the patch: ./cin -r prova_1.rc [plain text, no xml file] [...] ** rendered 0 frames in 0.000 secs, 0.000 fps Session time: 0:00:00 Cpu time: user: 0:00:00.118 sys: 0:00:00.043 ./cin -r expanders.txt [plain text, no xml file] [...] ** rendered 0 frames in 0.000 secs, 0.000 fps Session time: 0:00:00 Cpu time: user: 0:00:00.111 sys: 0:00:00.034 With the patch: ./cin -r expanders.txt [...] Not XML file!