Updated the sampling method from Gaussian to Normalized Uniform Interval 

Changed the sampling method to Normalized Uniform Interval so that the code can be safely extended to Deep Belief Networks.  This sampling interval was initially proposed in the following reference

Reference: Understanding the difficulty of training deep feedforward neural networks by Xavier Glorot and Yoshua Bengio

Authors elucidate the need for this interval as 
> We suggest the following initialization procedure to approximately satisfy our objectives of maintaining activation variances and back propagated gradient variance as one moves up and down the network