Er... what do you don't get it about?
That link just linked us to a bunch of lenses. They are different lenses for m4/3 camera.
As for is it worth the 1.5k, it is difficult for any of us to tell you. To me, it is worth that much of money because the 12-40mm f2.8 PRO is a fabulous lens and is in a totally different league as the 14-42mm lens. But can you get good result with a 14-42mm lens? Yes, you can. I have survive for more than a year with the 14-42 and up till today, I still didn't find the need for the 12-40mm f2.8.
As to the differences between the EM1 and EM10... from reviews, it is noted that the EM1 do have better overall performance including sharpness, contrast and noise performance and it had a better Image stabilizing system. But do you need all those? Nobody can safely and responsibly tell you. Because all these are up to oneself. EM10 is a great camera, it will serve you well.
All that said, I would always advise people to buy within their budget and buy the best within that budget. However, do keep in mind that there is really no point stretching your budget till you feel the pinch. Photography is suppose to be a very fun hobby, no point tightening your belt and get something top of the class.
Also I would really advise you not to look at prime or single focal range lenses, yet. Not that I don't believe you can do it, but I have seen many newbies (myself included) jumping into the prime lenses only to dump them in the dry cabinet for a while. Zoom lenses are more feasible for most people, at least until they know which focal length they used most of the time, then get a prime lens that is suitable for the length. For example, use your kit lens (14-42mm or 12-50mm) for most of the time, then as time goes, you found that you only use one focal length (say, 12mm) most of the time (say, around 80 to 90%), then you invest in a 12mm lens.