Change most tests to make use of assert_raise returning the raised
exception rather than relying on a combination of flunk + rescue to
check for exception types/messages.

JSON.{dump,generate} offered by the JSON gem is not compatiable with
Rails at the moment and can cause a lot of subtle bugs when passed
certain data structures. This changed all direct usage of the JSON gem
in internal Rails code to always go through AS::JSON.{decode,encode}.

We also shouldn't be implementing `to_json` most of the time, and
these occurances are replaced with an equivilent `as_json`
implementation to avoid problems down the road.

See [1] for all the juicy details.

[1]: intridea/multi_json#138 (comment)

* Fix named route collision in mount test fixture
* Update controller named route precedence test

Many named routes have keys that are required to successfully resolve. If a key is left off like this:

    <%= link_to 'user', user_path %>

This will produce an error like this:

    No route matches {:action=>"show", :controller=>"users"}

Since we know that the :id is missing, we can add extra debugging information to the error message.

    No route matches {:action=>"show", :controller=>"users"} missing required keys: [:id]


This will help new and seasoned developers look closer at their parameters. I've also subclassed the routing error to be clear that this error is a result of attempting to generate a url and not because the user is trying to visit a bad url. 

While this may sound trivial this error message is misleading and confuses most developers. The important part isn't what's in the options its's what's missing. Adding this information to the error message will make debugging much more obvious. 

This is the sister pull request of https://github.com/rails/journey/pull/44 which will be required to get they missing keys into the correct error message. 

Example Development Error in Rails: http://cl.ly/image/3S0T0n1T3421

This fixes the following scenario:

    resources :contacts do
      post 'new', action: 'new', on: :collection, as: :new
    end

Where the /new path is not generated because it's considered a canonical
action, part of the normal resource actions:

    new_contacts POST   /contacts(.:format)          contacts#new

Fixes #2999

In the current router DSL, using the +match+ DSL
method will match all verbs for the path to the
specified endpoint.

In the vast majority of cases, people are
currently using +match+ when they actually mean
+get+. This introduces security implications.

This commit disallows calling +match+ without
an HTTP verb constraint by default. To explicitly
match all verbs, this commit also adds a
:via => :all option to +match+.

Closes #5964

Allow the root route helper to accept just a string

PATCH is the correct HTML verb to map to the #update action. The
semantics for PATCH allows for partial updates, whereas PUT requires a
complete replacement.

Changes:
* adds config.default_method_for_update you can set to :patch
* optionally use PATCH instead of PUT in resource routes and forms
* adds the #patch verb to routes to detect PATCH requests
* adds #patch? to Request
* changes documentation and comments to indicate support for PATCH

This change maintains complete backwards compatibility by keeping :put
as the default for config.default_method_for_update.

symbol nodes.  Fixes #4585

Named Routes shouldn't override existing ones (currently route recognition goes with the earliest match, named routes use the latest match)

When a route references a missing controller, raise ActionController::RoutingError with a clearer message

raise an error if the old router draw method is used, along with a message advising them to either upgrade their routes or add rails_legacy_mapper to their Gemfile