GSoC 2014: Standard Extreme Learning Machines

Finished implementing the standard extreme learning machines (ELMs). I am getting the following results with 550 hidden neurons against the digits datasets,

Training accuracy using the logistic activation function: 0.999444
Training accuracy using the tanh activation function: 1.000000

Fortunately, this algorithm is much easier to implement and debug than multi-layer perceptron :).
I will push a test file soon.

@ogrisel , @larsmans
Indeed, it looks more as a sequential algorithm.
Maybe I should name it `sequential_lsqr` as in the paper? http://www.ntu.edu.sg/home/egbhuang/pdf/OS-ELM-TNN.pdf