Fixed bug reported by Andras Muranyi where clearing a preset would erroneously...

Fixed bug reported by Andras Muranyi where clearing a preset would erroneously delete two adjacent presets. Added "sort n" command that allows linear sorting starting with number n (default 0). Improved output from preset_hub_store (via hub's outlet) to report failed creation of presets with negative numbers (successful creation of preset n would output "store n 1," while failed one would output "store n 0").