Incorporate changes from Shugo's PR 914 (fix detailed takeoff example), and fixed a few other issues with Solved 2DOF.

[Kenneth-T-Moore]

Summary

This PR incorporates changes from #914 that fixed some issues with the detailed takeoff example:

• Added a mass constraint for the start of the solved 2dof trajectory.
• Added initial mass guesses to the takeoff and landing examples.
• Reduced the number of segments in the takeoff phases.

In addition, the following changes have been made:

• Changed the solved 2DOF mass units from 'kg' to 'lbm' to be consistent with the units in the ode for the majority of the phases.
• Fixed a bug that prevented the initial_bounds and initial_ref from being set in the solved 2DOF time options.
• Added consistent scaling to the angle of attack linkage constraint (note: a dymos bug prevents this from working properly, but a fix is incoming.)

In the phase_info for the detailed takeoff example:

• Tuned some scaling factors for desvars and constraints.
• Added missing altitude constraint for obstacle at end of BC.
• Made initial distances consistent with each other.
• Removed a redundant altitude constraint at P2.

Related Issues

• Resolves #

Backwards incompatibilities

None

New Dependencies

None