ContentDialog: Input & Focus Management

Summary of changes:

- When a dialog has only one button, make it right-aligned and half the
  width of the dialog.
- Exposed dispatchEvent on WinJS.Application as _dispatchEvent so that
  tests can fire Application events synchronously.
- Input & focus management
  - Connect escape key and hardware back button to hide
  - Eat pointer events and clicks
  - Restore focus when dialog is dismissed
  - Prevent focus from escaping the dialog. Monitor all focus moves and
    if one is outside of the dialog, put focus back inside the dialog.
    But allow focus to move into Flyouts.
  - Avoid leaks when listening to events on global objects. Apply the
    _ElementUtilities._globalListener pattern to WinJS.Application and
    document.documentElement.
- API changes:
  - CSS class name changes
    - win-contentdialog-body -> win-contentdialog-dialog
    - win-contentdialog-dimcontent -> win-contentdialog-backgroundoverlay
    - win-contentdialog-content is now public
    - win-contentdialog-commands is now public
  - Property changes
    - isPrimaryCommandDisabled -> primaryCommandDisabled
    - isSecondaryCommandDisabled -> secondaryCommandDisabled
    - Exposed enum WinJS.UI.ContentDialog.DismissalReason
 Toolbar/AppBar API review section enum values updates (add primary, secondary values)
Merge branch 'master' of github.com:winjs/winjs
Fix issue622
Update appbar tests to use primary/secondary sections by default instead of deprecated values
Toolbar redline updates, remove win-toolbar-overfloware-mixed support.

The height of inline menu will be 4.5 x 44px, regarless of whether there are separators or not. Per discussion with designers.
Merge pull request #623 from spankyj/issue622

Fixes #622
Merge branch 'master' into AmazingJaze/listviewstriping