Add drop command.

Signed-off-by: nppangband <nppangbanddev@verizon.net>
Add drop command.

Signed-off-by: nppangband <nppangbanddev@verizon.net>
Merge branch 'diego' of https://github.com/nppangband/NPPAngband_QT.git into Jeff
Merge branch 'Jeff'