To make dumping/loading designs match other dumping/loading buttons (terrain, acre and so on)
+ clicking on "Dump/Load Design" will draw a context menu with 4 options (2 if it's only one design pattern e.g. town flag).
+ when loading designs, I made the Listbox with the design names repopulate (update names) and select the user-selected design instead of going to index = 0;
+ when loading all designs I open a prompt to update "values" or not, instead of by default updating them.
+ fixed file name of dumped singular pro designs to .nhpd instead of .nhd lol
