#399 Save target files before executing custom tool menu item

The tools menu has a number of macros for target files
that may be passed to the custom command. However,
these files are not saved before invoking the command.
If the command modifies the files, there is a risk of
inadvertantly loosing changes.

A check-box option to save any referenced targets in
the "parameters" field would provide a neat solution.
The macros in question are:

<PROJECTFILE>
<SOURCENAME>
<SOURCESPCLIST>

Clifford