Bug fixes for gates at edges of short segments

This MR addresses the bug where every short segment has a gate applied at the start and stop of the segment. This resulted in extra gates being applied periodically. The periodic nature of the gates is particularly problematic for CW searches as this can (and did for the G01 gate generation) introduce a comb into the data.

This MR also includes changes to the start and stop times of the entire analysis. Now, these periods cannot be gated by default to prevent any discontinuities between different analysis periods.

Closes #14 (closed)