Stacking status should be more descriptive during the stacking process

[echer80111]

Would be really nice to know what the program is working on at a given point during the stacking.

A few ideas for this:

1. Simple line of text that displays the active calculation step taking place. Something like "Voxelizing...", "Determining placements for [part name]", "Trying larger box."
2. A total part counter alongside the progress bar, to indicate how many parts have been placed.
3. A part counter next to the Parts table, indicating how many of each part have been successfully placed.