[MRG] 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
@IssamLaradji how do you generate those figures? Using graphviz? If so can you please inclode the graph definition in a hidden "comment" block, see: http://docutils.sourceforge.net/docs/user/rst/quickref.html#comments