Bug: remove_components crash

[cleong110]

Introduced by me in #148 .

https://github.com/sign-language-processing/pose/blob/master/src/python/pose_format/pose.py#L221 this line incorrectly assumes that all the components are in the points_dict. So if you call it with remove_components([], points_to_remove={"POSE_LANDMARKS":[]}) it crashes, because FACE_LANDMARKS is not in there!

Working on a PR and test.

[cleong110]

There's so many interesting edge cases to consider. For example

• remove_components("POSE_LANDMARKS",{"POSE_LANDMARKS":[})
• remove_components("POSE_LANDMARKS",{"POSE_LANDMARKS":["SOMETHINGINVALID"]})
• remove_components([],{"POSE_LANDMARKS":["LEFT_KNEE"]})

[cleong110]

Test Cases to check:

Cases where the components/points ARE in in the file

• remove [X] component, X:Y point: expect X component to be gone completely, X.Y part doesn't do anything.
• Remove [] (no components), X:Y Point: expect only X.Y to be gone
• Remove X Component, A:B Point, X is gone, A:B is gone, all others in A are fine.

Cases where the components/points are NOT in the file

• Remove points that don't exist -> nothing happens, but maybe print a warning?
• Remove components that don't exist -> same
• Remove points from components that don't exist -> same

[cleong110]

Test cases implemented! Looks like the new implementation works!