[Module-build-general] copy_if_modified() now takes named parameters

[Ken W. <ke...@ma...>]

Hey,

I'm about to commit a patch that makes copy_if_modified() take named 
parameters.  I've done so in a way that lets old-style 
$self->copy_if_modified($from, $to_dir, $flatten) invocations keep 
working, but they should probably be considered deprecated.

I've also added these docs about the method:

--------------------------------------------------------
=item copy_if_modified()

Takes the file in the C<from> parameter and copies it to the file in
the C<to> parameter, or the directory in the C<to_dir> parameter, if
the file has changed since it was last copied (or if it doesn't exist
in the new location).  An optional C<flatten> parameter will copy into
C<to_dir> without replicating the directory structure in C<from>;
otherwise the entire structure will be copied into C<to_dir>.

Any directories that need to be created in order to perform the
copying will be automatically created.
--------------------------------------------------------

I needed to do this to support the new alternative-layouts stuff I'm 
about to commit.

  -Ken