Amend #save! and #close!
Amend #save! and #close!

#close! will not always save changes, so don't say it will.
However, retain the bang since it has the potential to make
permanent changes.

Update #save! to ensure that changes made to the current XMP
object will be saved to disk; this wasn't happening if
xmp_files_put_xmp() wasn't called. Also update the documentation
on file saving.
mistydemeo/fasttrack