Add a helpful warning

Because almost every property on a class definition is a function, it's
easy to accidentally say this out of habit:

````javascript

App.MyController = Ember.Controller.extend({
  actions: function() {
    doThing: function() { ... }
  }
});

````

When you meant to say this:

````javascript

App.MyController = Ember.Controller.extend({
  actions: {
    doThing: function() { ... }
  }
});

````

This doesn't product any errors or warning, it just makes your handlers
invisible. My change adds an assertion.
Merge pull request #3749 from ef4/actions-warning

Actions warning
Fixes incorrect truncation
Merge pull request #3811 from twokul/fix-for-set-path

Fixes incorrect truncation
Adds truncation tests
Merge pull request #3812 from twokul/truncation-tests

Adds truncation tests
[BUGFIX beta] Make flag LOG_TRANSITIONS_INTERNAL work again

The `router.log` method is set to `Ember.Logger.debug` when the
LOG_TRANSITIONS_INTERNAL flag on the application is set. Since the
`namespace` at the time of the check is `undefined`, this doesn't work.

This fix moves the check into the routers' `init` method.

This closes #3813
Merge pull request #3814 from pangratz/fix/router_LOG_TRANSITIONS_INTERNAL

[BUGFIX beta] Make flag LOG_TRANSITIONS_INTERNAL work again