New instantaneous phase function using Hilbert transform.

Phase and relative phase for SHCs.

Also a simple function to trim SHC data to an integer number of periods in order to mitigate aliasing: shc_wholeperiods().

Also a private function wrap() for rewrapping unwrapped data output from Matlab's unwrap().

Signed-off-by: Andrew D. Horchler <adh9@case.edu>