Most of the Android phones that offer fast charging use Qualcomm's Quick Charge which requires a Snapdragon processor. iPhones use a different processor so perhaps it isn't supported?
https://www.qualcomm.com/products/snapdragon/quick-charge
As far as whether the iPhone 7 will support it, I haven't read any rumors that would suggest this. It's possible, but we won't know until it's announced.
If you're interested in charging faster than what the standard charger provides, this is a good recommendation. On my iPhone 6S plus I can get 1% per minute up to about 80% then it slows down.