v0.3.0

• All Modes now have a Family associated type instead of a Base type.
• Mode::get_transition() has been replaced by Mode::swap(), and Transition has been removed entirely.
• Mode::swap() takes an input parameter and can return a value, if desired, based on the Input and Output types specified by Mode::Family.
• Mode::as_base() and Mode::as_base_mut() have been removed.
• Added new Mode traits in separate modules that accept pointer types such as Box, std::rc::Rc, and std::sync::Arc.
• Automaton now stores the current Mode in-place, and is parameterized based on the Family type instead of the Base type.
• The Family trait provides convenience functions for creating an Automaton that is compatible with the Family implementation in question.
• Added guides for upgrading from version ^0.2 to version 0.3 of mode.