Bump angular to 2.4.x

[DorianGrey]

There are still some issues that prevent this merge; so this is mostly for progress tracking.

• Strict mode violation of shipped umd bundle, which causes the unit tests to fail: Strict mode syntax error when running @angular/compiler 2.3.0 in PhantomJS angular/angular#13301
• @ngtools/webpack plugin was not adopted yet, which seems to cause errors when attempting to use AoT mode:

/node_modules/@ngtools/webpack/src/plugin.js:136
        this._reflectorHost = new ngCompiler.ReflectorHost(this._program, this._compilerHost, this._angularCompilerOptions);
                              ^
TypeError: ngCompiler.ReflectorHost is not a constructor

• 2016-12-15:
  • The first issue was fixed by angular 2.3.1 release.
  • The second issue might be fixed by feat(deps): Unblock the version of Angular to >= 2.3 angular/angular-cli#3569
• 2016-12-12:
  • The second issue was resolved in version 1.2.1 of @ngtools/webpack.
  • Had to omit angular 2.3.x since it contained a bug that caused AOT doesn't work with angular 2.3.* + ngrx/store#295 . This was fixed in 2.4.0 .