simplify interface

[semibran]

Addresses #16 and #20.

[jwagner]

Hello semibran,

While the interface you propose is elegant it has significant drawbacks:

• It breaks backwards compatibility
• It is significantly slower (~20% according for noise2D to a quick run of the benchmark)

The interface of simplex-noise.js has been designed in this way for a reason, monomorphic code is nearly always faster in javascript. See [https://mrale.ph/blog/2015/01/11/whats-up-with-monomorphism.html](What's up with monomorphism?) for some more details on that.

So while I appreciate your effort this is not the direction I want to take this library in.

There are places where elegance trumps performance and practicality so it could be a great idea to create a javascript library based on simplex-noise that just implements the simplified interface on top of it.