My sampler update

Created by: apcarp

This update includes an service that performs a mySampler compatible sampling of an event stream based on the BoundaryAwareStream class. Unit tests included.

The old method for getting a mySampler like stream is left intact for backwards compatibility. Documentation about deprecation, etc. may need to be added. The old method did not update time stamps when returning the sampled stream, while the new method generates artificial Event objects at the sample times. The new method also supports multiple event types, not just FloatEvents.