Add parent route fragments to Match

[orestis]

When having a route structure like so:

["/messages"
 {:data "..."}
 [""
  {:name :message-list}]
 ["/:message-id"
  {:name :message-detail}]]

When /messages/abc is matched, the Match result only indicate that the route :message-detail was matched. Sometimes it's useful to also have all the "parent" routes above it available as a vector.

The proposed workaround of having a custom key (like :section which could be either a set or a vector) is good enough for me, and potentially solves my use case even better, so perhaps this is a moot issue anyway.