New "GetDirectory" function

Same as "StripDirectory", but it returns a new string instead of
modifying an existing one.
Limit mousewheel hooking on metadata browser to compiled EXE only

This should fix some rare but obnoxious GPF occurrences in the IDE
Preserve metadata in saved images (per user's preference)

See discussion in Issue #59.  I'm not going to close the issue until I
do a bit more testing, but at present the matter looks to be resolved.

Note that this only implements 3 of the 4 current metadata preferences.
"Remove privacy tags" is still being worked on.