This is just my opinion, but a gaming laptop and a laptop for college are two completely different things, and you will end up spending a lot of money on something that will not fit your needs. I'm not saying that you shouldn't play games at college. Go for it, but a gaming laptop is not the way to do it. You will be buying a heavy, hot, loud, expensive computer with poor battery life. In comparison to a gaming desktop, performance will be terrible, and your gaming set up will be awkward and cramped.
The ONLY reason to get a gaming laptop is if you really need to play AAA games with medium settings on the go. Really consider if you need power on the go. And no, programming does not take power. I'm a college student, and one of the guys I'm living with is finishing up a computer science major on an iPad (wouldn't recommend it, just because of the inconvenience of touch, but it does everything he needs power wise).
Now, here is what I would recommend. Get a refurbished 2012 iMac, i7, gtx 680mx, 1TB fusion drive for 2000$. It has better graphics performance than the maxed out 2013 model, and the 680mx is overclockable. Check it out on youtube. If you ever need to do any heavy work, it is a powerhouse. You will be able to run most modern games at 1440p, high settings. Wait until the new MBA comes out, and get a baseline model to do your schoolwork on. Or, if it doesn't come out by the time you need it, get a 13" rMBP for either 1200$ (128GB/4GB) or 1400$(256GB/8GB).It will come out to a little under 3500$.
If you really really want the 15" rMBP, check out the 2012 model. The 2013 model barely improved. The baseline graphics are actually worse, the haswell processor doesn't improve performance, and barely improves battery life. You can pick up a 256GB/8GB model used on ebay for around 1400$, and it will be comprable in performance to the 2700$ 2013 model (at least graphics wise). You can still get the iMac with the best graphics performance available for 2000$, and stay in budget
All the options aside, I have two pieces of advice. Gaming performance on laptops have a massive premium, so look into getting a powerful desktop and a portable laptop. Second, you are looking to spend 3500$, and since you are on this forum, it looks like you want to do research before you make a decision. There are many websites that do performance tests on graphics cards, laptops, and desktops. Check out anandtech, videocardbenchmark, and geekbench. The best computer is not always the most expensive computer, especially this year.
Sorry if I came across a little rude, I just don't want you to waste your money. With 3500$, you can get some really great performance. I know it can be hard to save money, so I won't tell you to haha (I have a hackintosh with a gtx 770, an iPad air, and I will probably buy a MBA when the new one comes out). If you want to experiment, and you really want performance, a hackintosh is awesome if you do it right. For about 1000$ In components, and 500$ in peripherals (sound system, decent monitor, keyboard, and mouse) you can get a sick computer. I would still personally recommend an iMac, because it is a pain in the ass to maintain a hackintosh, you will get comprable performance, and the iMac is beautiful. I threw a lot of very vague information at you. If you want to know more about any of the options, I can direct you to the correct places.
TL;DR: Don't waste your money on a 2013 model, 2012 models of the 15" rMBP and the iMac are even better than their 2013 counterparts in terms of graphics.
Sorry for the long post, Best,
Matt