templatekw: change {file_copies} behaviour, add {file_copies_switch}
{file_copies} template now displays file copies with or without the --copies
switch being set. A new {file_copies_switch} template implements the former
behaviour.
#!/bin/sh
hg init a
cd a
hg init b
echo x > b/x
echo '# should print nothing'
hg add b
hg st
echo '# should fail'
hg st b/x
hg add b/x
echo '# should fail'
hg add b b/x
hg st
echo '# should arguably print nothing'
hg st b
echo a > a
hg ci -Ama a
echo '# should fail'
hg mv a b
hg st