Let OakFinderLabelChooser draw and manage it's own title

This removes the need to create and manage a separate menu item
as a placeholder for the title of the color swatch in the file
browser action menu.
Support text attributes with VoiceOver

VoiceOver can announce text formatting, such as bold font, italics,
underline, font, etc., as well as whether text is misspelled. For this,
it needs the AXAttributedStringForRange attribute supported. This commit
does exactly that.

Testing can be done in this way (VO stands for Ctrl-Option):

* first interact with the text (VO-Shift-down arrow when standing
  on the text element)
* to announce text attributes for character after cursor, press VO-T
* to seek for next:
  * misspelled text: VO-Cmd-E
  * color change:    VO-Cmd-K
  * underlined text: VO-Cmd-U
  * many more (see VO-H-H, "Find", close help with Esc)
* to seek for previous *: just add Shift to the shortcut

Some attributes remain to be supported (full list of attributes is available at: https://developer.apple.com/library/mac/documentation/cocoa/reference/applicationkit/Protocols/NSAccessibility_Protocol/Reference/Reference.html#//apple_ref/doc/uid/20000945-SW53).

The misspelled text VoiceOver support can be used nicely with TextMate's
spelling support:

1. the user finds next mistake with VO-Cmd-E, hears the misspelled word,
   perhaps reads it on a braille display
2. the user then presses Cmd-; to show the spelling menu for that word
   and chooses the desired resolution (apply suggested correction etc.)
3. go back to step 1. :-)
Ensure that at least 8 tabs stay open when auto-pruning
Clear all web view delegates during dealloc
Add leak watcher and some debug output
Do not re-use closed HTML output windows
Fix window.close() for HTML output embedded in main window
Only first call to window.close() would have an effect

This is a workaround for https://bugs.webkit.org/show_bug.cgi?id=121232
Intersect left/right scope for rendering soft break nodes

This is only relevant for indented soft wrap where e.g. the text following the soft break is underlined: Previously we would then render an underline for the soft break node itself (which normally consists of whitespace).
Add icon definitions to CFBundleDocumentTypes

Works around a bug where icons are not inherited from the UTI definitions.
Let tab menu methods fallback on active tab

These normally require that the sender is an NSIndexSet or has one as its represented object, but with this commit, they will also be usable when there is no index set available, and will then simply use the active tab.
Add action method for closing tabs to the right
Add menu validation for close tabs related actions
Add IBAction to methods
Add Sticky and Close Tabs to the Right to File menu

The title of the Sticky item is nonsensical, but I couldn’t come up with anything good.

Closes #1110.