generates a set of spiketrains,at different noise levels but with the same neuronal firing. input allMeans: collection of mean waveforms realWaveformsInd: real waveforms to use nrsamples:# samples to generate,sampled at 100000Hz noiseStds: vector of noise stds to generate returns spiketrainsAll: cell array of spike trains for each noise level realWaveformsInd:same as input noiseWaveformsInd:which of the mean waveforms were chosen to be used for noise spiketimes: cell array of points of time when neurons fire (for each neuron one element in cell array). waveformsOrig: cell array of cell arrays, orig waveforms of each noise level for each neuron. scalingFactorSpikes: scaling factor used for each of the real (=neuron) mean waveforms. urut/dec04