Mac Fixes

These changes should resolve the following:

1664: Windows (except for the main window) can be closed. They can be reopened by using the "Window" menu. Availability is based on the player's subwindow flag settings.

1701: The preferred version is displayed properly. The detailed version is shown in the "About Angband" window.

506: A new target (safe-install) has been added. This will build Angband to use a separate set of preferences and data directories based on the version.

880/1460: A new "Command" menu has been added, which sends the corresponding Angband command to the game. Right now, it is only configured to send the commands that were causing problems (~, [, ], {, }). However, the menu can be modified by editing CommandMenu.plist.