Deep Learning frameworks: a review before finishing 2016

I love to visit Machine Learning meetups organized in Madrid (Spain) and I'm a regular attendant to Tensorflow Madrid and Machine Learning Spain groups. At least I was until the begining of the Self-Driving Car course, but that is another story. The fact is that too often, during "pizza & beer" time or networking I heard people talking about Deep Learning. Sentences like "where should I begin? Tensorflow is the most popular, isn't it?",