v0.3.18

Read the whole Rails route table, and add Grape (#229)

Routes now come from every config/routes.rb and every .rb under a
config/routes/ directory at any depth, each parsed under the prefix that
draws or mounts it, with `mount` resolved to the mounted engine's own
route file. Routes carry a handled_by edge to their controller action,
the walk descends into Ruby control flow, and classes carry a
rails_component prop.

Grape is identified by transitive inheritance rather than by a route
file, computed from the superclass props the AST pass already emits: a
codebase typically has one class inheriting Grape directly and hundreds
inheriting that, and deriving the set from facts that exist already costs
no extra I/O where there is no Grape.

Also drops `lib` from the ember util layer. It is wrong on Ember's own
terms, and layer matching is by path segment, so in a mixed repo it
claimed Ruby lib directories and made almost every edge out of them a
violation.