TrackEditor: Improvements and bugfixes

[tomas-nestorovic]

The Track Editor (available after clicking on a track head number in Track Map) was introduced in Issue #57 as a lightweight visualization of fluxes contained in a KryoFlux Stream file. However, since its introduction, the code base is constantly growing and makes the KryoFlux Issue #57 disorganized.

This issue is thus intended as specialized continuation of the KryoFlux issue in which all new modifications of the Track Editor component should be committed to. There's currently no particular goal set to close the issue, so let's keep it open at the moment indefinitely (to be changed in the future).