0.9.4-alpha

• Fix issue where a dispatch value x was not considered to be preferred over y if an indirect preference was defined (i.e., via prefer-method) for an ancestor of x over y or for x over an ancestor of y. (#22)
• Remove methodical.util/prefers? since its logic was incorrect and a adding a working implementation would require access to the hierarchy of a Dispatcher; but this is not something exposed in the interface. (Not all Dispatchers have exactly one hierarchy). methodical.impl.dispacter.common/prefers? can be used if you know what the hierarchy is. (#23)