To line up better with other places in Moose where we accept optional
parameters (-metaclass, etc), and for better compatibility with other
modules which might add additional role parameters
(MooseX::Role::Parameterized, for instance), this branch renames the
'alias' and 'excludes' options that roles can take to '-alias' and
'-excludes'. The branch currently accepts both names for the options,
but ideally sometime soon, the old names could be deprecated and
removed. The idea behind this is to reserve a namespace for core options
("things starting with -") so that extensions can use other option names
without interfering with Moose.-doy
