Please add Leva Institute of Qom and University of Tehran Calculation Methods, these methods are used by followers of the Jafari school worldwide. I think it'll be something very easy to add, the only difference will be that Maghrib will be based on an angle instead of being at sunset. This simple addition will make Pillars more inclusive, and will allow 20% of the worldwide Muslim population to make the switch to this app with ease, rather than having to manually change angles and add offsets for maghrib :)

http://praytimes.org/wiki/Calculation_Methods

Leva Institute parameters
Fajr angle - 16°
Zuhr - same as others
Asr - same as others, choose between Shafi or Hanafi.
Maghrib angle - 4°
Isha angle - 14°

University of Tehran
Fajr angle - 17.7°
Zuhr - same as others
Asr - same as others, choose between Shafi or Hanafi.
Maghrib angle - 4.5°
Isha angle - 14°