ENH/TST: Warn user if image looks like color (has 3 or 4 in its shape).
Removed unused code, updated deps.

LinkOnDisk and Trajectories were supplanted by framewise_data.py

This removed the dependency on yaml_serialize, which was no longer
actually used.

I will restore the wire-tracking code when it is in better shape.
Merge pull request #72 from danielballan/warn-on-color-image

ENH/TST: Warn user if image looks like color (has 3 or 4 in its shape).
Merge pull request #73 from danielballan/cleanup

Removed unused code, updated deps.