Spike-signal coherence

Obtains a measure of coherence between a set of spike times and a continuous signal (e.g. the local field potential - known as spike-field coherence), as a function of frequency (Hz). The coherence value is bound between 1 and 0, for a perfect and a complete lack of coherence respectively. In the case of spike-field coherence, a coherence value of 1 at a particular frequency indicates spikes perfectly phase locked to this frequency component within the local field potential. A full explanation of the function's usage is included within the function. Please feel free to get in contact for suggested improvements and/or the detection of bugs.