Add module for aligning local timestamps to the Harp clock

[bruno-f-cruz]

First discussed in harp-tech/harp-python#38

I would suggest adding this to harp.data namespace.
it should:

• From an array of points with a specified sample rate, return the timestamp information and the sample corresponding to that timestamp
• From an array of timestamps of toggles (ts, 0/1) return the harp timestamp and the provided timestamp