I am shocked that people keep repeating the timelines Tesla has given for the gigafactory, and for the model 3 car as if they are in any way likely to come true. I can basically guarantee that neither one will be the case. Tesla is chronically late with their products, and these will be similar. remember, gigafactory broke ground last month, the chadmeo adapter was available a year ago, the model x will ship last year, the centre console will be available a year ago, etc etc.
Gigafactory hasn't broken ground yet (no matter what people say about various construction projects, I have trouble believing that Tesla would miss the PR opportunity of a ground breaking!) A factory like that takes time to build and outfit, it won't be finished and producing batteries by 2016-2017. As for model 3 they haven't even shown off an artist's rendering yet, and again, these take time.
If I had to make a reasonable guess on timelines, I'm going to say gigafactory and model 3 together in 2018 but that counts on a lot of things going right, so the timeline could yet slip further.
Somewhat off topic, but it's because Elon specifically stated that it would be represented by 3 lines, people have been assuming three horizontal lines instead of 3 vertical ones, but nowhere has anyone at Tesla indicated the orientation of said lines.