Ascendant calculation module

[TheMascot]

First of all I would like to appreciate the amount of work you put in this library @commenthol! Absolutely amazing!

I used this library for planetary calculations to build a basic astrology calculator. As far as I can tell there is no easy method in the library to calculate the current ascendant based on the observer's location on Earth and the correct time. I wrote the method with a basic location format converter. I coded the test file also and npm test returns all green.

I'm kind of new in the github space but red that every pull request should start as an issue. Honoring this possible method here is my issue. :)