change news description
<h2>News</h2>
-2017-12-14: [New teacher added: PytorchDataTeacher](https://github.com/facebookresearch/ParlAI/blob/master/parlai/core/pytorch_data_teacher.py)
+2017-12-14: Fast, multiprocessed data loading supported with [Pytorch data loader](https://github.com/facebookresearch/ParlAI/blob/master/parlai/core/pytorch_data_teacher.py)
2017-11-30: Several new tasks added: [SCAN](https://github.com/brendenlake/SCAN), [ConvAI](http://convai.io/data/), [NVLR](http://lic.nlp.cornell.edu/nlvr/) and [ISWLT14](http://wit3.fbk.eu).
