SHRED and SORT in the process bar misbehave in the one-step view #417

layout.js goStep (~305-311): idle, SHRED pages to the grinder step, not THE BIN, and the flash on .fcol.bincol does nothing because that column is not shown. During a batch goStep does not set userPaged, so the next draw jumps back to the step the batch is on and SHRED/SORT do nothing visible. Fix: in scene mode page SHRED to the BIN scene, flash the column on screen, and set userPaged = !!app.S.run as pageTo and the arrows do.