add performance test with notebook

The test is based on passing a function of randomly distributed peaks (gaussians or lorentzians), and testing if the learner is able to find them.

The test is designed to fail with the current state of adaptive, and to pass with and fix of the kind mentioned in #27 (closed).

I added a python test file, which for the moment is not running alone, and needs to be run in a jupyter notebook. The corresponding jupyter notebook to see what the test is doing is also included.