update dependents test
test for mutual requires
Stop using Role::Tiny's backcompat hack
changelog mutual requires fix
more testing for create_class_with_roles
mark inhaled Moose roles with is_role
prevent importing Moo into a Role::Tiny
Remove MooX::Types from xt tests

Having MooX::Types in the xt tests creates a circular dependency for
developers.  While this isn't strictly a problem, we can easily test the
type inflation code without using it.
add developer requirements to Makefile.PL
add Travis CI config