Add utility for combining SGM trajectories

[crecine]

Desired capability or behavior.

Currently the FlexibleTraj is initialized with a dictionary of the phases that will comprise it. To combine two trajectories, the dictionaries must be combined before a new trajectory is instantiated. There should be a way to combine two trajectories after they have been created.

Is your feature request related to a problem? Please describe.

No response

Associated Bug Report

No response

[jkirk5]

Marked as wontfix until future decisions on additional SGM feature enhancement

[crecine]

I think this is unnecessary with the latest phase_info unification