[FEATURE] Impl. buildRouteInfoMetadata

[chadhietala]

This introduces buildRouteInfoMetadata as specified by RFC#398

[rwjblue]

not ok 2 Docs coverage > classitems > No extraneous classitems
  ---
  message: "If you intentionally removed a public API method, please udpate tests/docs/expected.js. Otherwise, documentation is missing, incorrectly formatted, or in a directory that is not watched by yuidoc. All files containing documentation must have a yuidoc class declaration."
  severity: failed
  actual: [
  "metadata"
]
  expected: []
  stack:     at Object.<anonymous> (/home/travis/build/emberjs/ember.js/tests/docs/coverage-test.js:33:14)
  ...
1..2
# pass 1
# skip 0
# todo 0
# fail 1
error Command failed with exit code 1.

I think you need to add a new entry to the fixture of all the "classitems".

[rwjblue]

CI job passed here: https://travis-ci.org/emberjs/ember.js/builds/466100659