Add path simplification option

[w8r]

through @mourner's Douglas-Peucker simplification algorithm
read it from styles as a parameter
also maybe add method for that

[blanchg]

All you need to do is import @turfjs/simplify then do it on the input to the render

features = simplify(features, { tolerance: 0.02});
let svg = renderer.type('type').render(features);