coherence2: Calculates the coherence between two series
In driegert/transfer: Frequency Domain Transfer Function Estimation Tools

Estimates the frequency domain coherence using the multitaper method.

coherence2(x, y = NULL, blockSize = length(x), overlap = 0, deltat = 1,
  nw = 4, k = 7, nFFT = NULL, forward = TRUE, average = 1,
  msc = FALSE, freqRange = NULL, maxFreqOffset = NULL,
  prewhiten = FALSE, removePeriodic = TRUE, sigCutoff = NULL)

`x`	A `data.frame` whose columns are the time domain input series.
`y`	A `numeric` vector containing the response series.
`blockSize`	A `numeric` indicating the block sizes into which the input and response series will be partitioned.
`overlap`	A `numeric` between 0 and 1 indicating how much overlap should exist between adjacent blocks.
`deltat`	A `numeric` indicating the sample rate.
`nw`	A `numeric` indicating the time bandwidth parameter for estimating the Slepian data tapers.
`k`	A `numeric` indicating the number of tapers to use - should be approximately floor(2nw - 1) and no larger than floor(2nw).
`nFFT`	A `numeric` indicating the number of frequency bins to use (i.e. setting the zeropadding amount).
`forward`	Indicates whether the forward (TRUE) or reverse (FALSE) coherence should be calculated.
`average`	An `integer` representing how the average across blocks should be calculated; 0 - no average, return all the individual block information; 1 - average the cross and auto-spectra across blocks, then calculate the coherency 2 - estimate the coherency for each block, average the coherencey across blocks 3 - estimate the MSC for each block, average the MSC across blocks.
`freqRange`	A `numeric` vector containing two elements with the start and end location for the band on which to estimate the coherence.
`maxFreqOffset`	A `numeric` value indicating the maximum offset coherence to calculate in the specified band.
`prewhiten`	NOT YET IMPLEMENTED
`removePeriodic`	NOT YET IMPLEMENTED
`sigCutoff`	NOT YET IMPLEMENTED