need function to sync sample timings between records

[g2e]

This is a commonly encountered issue (meld, rotate, rotate_correlations, rotate3, hodogram, etc). Having the code in one place will simplify these rather complex functions and make writing new ones far easier.

This should probably allow for:

• adjusting the timing but not the data
• interpolating new data in the time domain
• interpolating new data in the frequency domain

Actually, TD interp is better than FD interp for a few reasons:

• speed
• no ringing
• allows unevenly sampled

So the FD option should probably not be included (omegashift is a workaround).