Verifies that git or cvs (depending on which SCM you're using)
don't print anything which isn't checked in.
Use .cvsignore or .gitignore for stuff you don't want to be reported.
Returns a true value if everything is checked in.
Call pretty much every function in this module. If $sloppy_scm is
set to a true value, the function will not enforce that everything
is checked in. $sloppy_scm defaults to false if omitted, therefore
enforcing that everything is checked in before the module is released.
$mpl_params specifies any parameters that have to be given to a
perl Makefile.PL call in your distribution.