changes IV3 to faster variant used elsewhere,
sort properties alphabetically,
simplify 'any' intersection,
un-duplicate database filtering
un-duplicate box/folder per-pkm processing
-25 lines, a little bit of reorganization since the form has grown since
its initial inception
use last char of file extension if available. edge case for pk[m]
considered:
pk[m] => 0x6D, -0x30 = 61d, &7 = 5, which prefers 6 instead of 7+ :)
adds a check for transferred pkm not having their CurrentHandler being
flagged as the save file (impossible for a transferred PKM to be still
handled by the OT).
Move System.Drawing usage out of Core to WinForms, as System.Drawing is
not in .NET Core/Standard. Simple methods to return resource name
strings have been added instead.
