Add od command for quick and easy orbit determination; Fixed PropUntil call

[ChristopherRabotin]

Use with measurement file from mission.

[ChristopherRabotin]

Still needs testing and adding of Kst plots.

[coveralls]

Coverage remained the same at 73.397% when pulling cf637b9 on issue-119 into 83c36fb on master.

[coveralls]

Coverage remained the same at 73.397% when pulling cf637b9 on issue-119 into 83c36fb on master.

[coveralls]

Coverage remained the same at 73.397% when pulling 745ecad on issue-119 into 83c36fb on master.

[coveralls]

Coverage decreased (-4.5%) to 68.87% when pulling 175e998 on issue-119 into 83c36fb on master.

[coveralls]

Coverage decreased (-4.3%) to 69.092% when pulling a142fda on issue-119 into 83c36fb on master.

[coveralls]

Coverage decreased (-4.0%) to 69.404% when pulling 5e3815c on issue-119 into 83c36fb on master.

[coveralls]

Coverage decreased (-4.3%) to 69.087% when pulling aade4dd on issue-119 into 83c36fb on master.

[coveralls]

Coverage decreased (-4.2%) to 69.223% when pulling 485e0d5 on issue-119 into 83c36fb on master.

[coveralls]

Coverage decreased (-4.2%) to 69.155% when pulling ba47f82 on issue-119 into 83c36fb on master.

[ChristopherRabotin]

Note: Cr is no longer tested and more specifically, seems broken.