[BUGFIX beta] Still update HTML5 history if the previous state was null

Fixes #3195, Closes #3580
Uses document.contains to figure if element exists in the DOM

addresses issue raised in
https://github.com/Polymer/ShadowDOM/issues/365#issuecomment-33509711
[FEATURE ember-handlebars-log-primitives] Enable by default.
[FEATURE ember-routing-bound-action-name] Fix assertion in deprecation.

If the action was in the root of the controller (not in an actions
hash), the lookup would find the actual action function itself,
resulting in us trying to trigger an invalid action (using the functions
toString value).
Merge pull request #4336 from rjackson/fix-deprecated-action-with-bound-lookup

[FEATURE ember-routing-bound-action-name] Fix assertion in deprecation.
Allow ES6ification of specific packages.

I used the `container` package as a guinea pig because it was already
assumed to be AMD in the rest of the code, and it does not live
elsewhere as an ES6 project already.

This uses the `es6-module-transpiler` with a custom generator script
(found in `bin/transpile-packages.js`). The custom script does a few
things differently from the `compile-modules` script that comes with the
transpiler:

* Modify the generated package names so that it matches current build
  tooling.

  Examples:

  * A file named `packages_es6/some-package/lib/blahzorz.js` will create a module named
    `some-package/blahzorz`.
  * A file named `packages_es6/some-package/tests/blammo_test.js` will
    create a module named `some-package/tests/blammo_test`.
* Any modules generated from the packages `lib/` directory will be
  transpiled from the `packages_es6/package-name/lib/` directory to the
  `packages/package-name/lib/main.js` file. This file will contain all
  of the modules from the package.
* Any modules generated from the packages `tests/` directory will be
  transpiled from `packages_es6/package-name/tests/` directory to the
  `packages/package-name/tests/package-name_test.js` file.
* At the end of the transpiled test file, all of the testing modules are
  required (to ensure the tests are run).
Merge pull request #4338 from rjackson/make-es6-possible

Allow ES6ification of specific packages.
[DOC] Update steps in README to build API docs
Merge pull request #4343 from bradfol/build-api-docs

[DOC] Update steps in README to build API docs
Fix minor typo: use `packageName` instead of hardcoding it
Update ember-dev to ensure transpile is done during dist.
Fixes the wait() test helper which was broken since the introduction of the async router
Merge pull request #4346 from rjackson/update-ember-dev

Update ember-dev to ensure transpile is done during dist.
Merge pull request #4347 from Herriau/fix_wait_testing_helper_async_router

Fixes the wait() test helper which was broken since the introduction of the async router
[BUGFIX beta] Do not rely on ember-testing-routing-helpers for async tests.
[FEATURE string-humanize] Revert feature.
Merge pull request #4348 from rjackson/fix-ember-testing-async-test

[BUGFIX beta] Do not rely on ember-testing-routing-helpers for async tests.
Merge pull request #4325 from rjackson/revert-string-humanize

[FEATURE string-humanize] Revert feature.
Merge pull request #4324 from rjackson/enable-log-primitives

[FEATURE ember-handlebars-log-primitives] Enable by default.
[DOC beta] Fix highlighting for Ember.Test namespace