Switch HTML output window back to NSWindow

The motivation for using a panel was to avoid the window from becoming main (so key equivalents would be sent to the document window, if not handled by the HTML output window). Unfortunately window ordering ignores non-main windows when a window is closed meaning that bringing up the Find dialog from an HTML output window and then closing it, would bring the current main window to front, eclipsing the HTML output window.
Let OS handle keys for Go to Tab submenu

My memory is a little vague here, but I believe the point of handling the menu keys was to workaround a bug in NSMenu.

The bug was that NSMenu would look at (the target of) cached menu items, probably for UI validation, so potentially sending methods to unretained objects, which could lead to a crash. Several workarounds were attempted (like clearing the target property after the menu had been displayed) but the only effective one was overloading key handling.

I’m quite sure though that this bug is no longer relevant.
Delete old file chooser code
Do not timestamp our code signing

This means that the signature will be invalid when the certificate expires, though it also means that codesign runs faster, and as my certificate is valid for another 4 years, people shouldn’t be using the builds released today when the certificate expires.
Account for strings with \0 characters

Previously we would truncate such strings.
Change our main menu keyhandling ≠overload

We manually handle the Bundles menu (like before) and now use performActionForItemAtIndex: to make the menu flash (although presently only for the default items).

For the other menus we now call super and let that handle it. This means it might go into the Bundles menu, even though or menu delegate (for that menu) will say there are no key equivalents. This is only a problem for keys which do match items, but where all the items it matches are not supposed to fire.
Add compatibility code for 10.7
Add OakFileManager

This is to be used with file actions done from the UI: Actions are undoable, proper dialogs will be shown for errors or to confirm permanent deletes on volumes without a trashcan (closes #589). Interface sounds will also be played (when moving, trashing, and duplicating items).

I decided not to use the asynchronous file system methods that NSWorkspace offer. Mainly because they can only be used for the initial operation, not during replay, as performing asynchronous operations during replay may cause issues if user moves quickly between items (something that seems to be an actual problem for Finder). The problem though only exist as long as we rely on NSUndoManager to manage the process.

Presently there is no API for batch operations, which leads to suboptimal action titles when performing multiple file system operations in the same undo group.
Remove undo/redo methods

This wasn’t functional (and not really in the responder chain).
Fix double indent
Use menu validation instead of manual disabling items

This is required if some of the menu item targets are not ‘self’ as we do not know if these targets can handle the action method.
Add undo support to file browser

This closes #17.