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
`That interval  is 1 / (n_features + n_hidden) if weight_scale='auto'; otherwise, the interval is the value given to weight_scale.`
=>
 If weight_scale='auto', then weight_scale is set to  1 / (n_features + n_hidden)?