Create performance tests

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I need to compare the performance between the map function, the for loop and the while loop. For each case, I need to compare the performance for Array and Float32Array.

Use jsperf.com to compare them.

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Regarding map vs for loop, check this out in both Chrome and Firefox.

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Regarding Array vs Float32Array, check this out in both Chrome and Firefox.

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Something worth mentioning: using Float32Array instead of Array increases the numerical error.

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Performance Tests for some FFT implementations:

http://jsperf.com/benchmark-for-fftw-js
http://jsperf.com/comparing-two-fft-functions/3