Repackaged the code as a framework and included the demo.

Packaging the code as a framework is mostly just a formality. It doesn’t
really change much, it just turns the code into a regular component.
What it does change is that the code now has its own Xcode settings,
which could make compatibility easier in the long run.

Including the demo in the main repository makes it easier to hack on
the library, since you can try the changes immediately. It also shows
how to bundle the framework into an app that uses it.
Created an umbrella header.

Now you can just `#import <MASShortcut/Shortcut.h>`.
Deleted an unneccessary prefix header for the framework target.
Updated documentation to point to the Demo target.
Added a unit testing target.
Introduced a separate header file for keycode definitions.
Converted keycode macros to plain functions.

Plain functions are less prone to bugs, the compiler understands
them better and can offer better error messages, and plain functions
can be refactored more easily.
Introduced a standalone MASShortcutValidator class to validate shortcuts.

It’s a natural simplification of the MASShortcut class. All MASShortcutView
objects use a shared validator by default, but can be reconfigured to use a
different validator if needed through the shortcutValidator property.
Introduced `instancetype` return type where appropriate.
Removed [MASShortcut shouldBypass].

It was never used and the recording can already be cancelled by Esc.
Trivial refactoring.

Forgot one `instancetype`, added `static` to NSString constants,
removed unneccessary @synthesize directives.
Removed -data and shortcutWithData: from MASShortcut.

Using NSKeyedUnarchiver and NSKeyedArchiver directly is almost the
same amount of typing and it’s much clearer what goes on.
Organized classes into Xcode folders.
Implemented NSCopying for MASShortcut.

This makes it possible to use shortcuts as collection keys.
Made the keyCode and modifierFlags properties read-only.

A shortcut is a good value type, it makes good sense to represent it
using an immutable object like NSNumber or NSString.
Implemented equality for shortcut objects.

Shortcuts are equal if and only if their key codes and modifier flags are.
Removed one forgotten modifierFlags setter.

It’s not needed now the class is effectively immutable.
Refactored the shortcut dispatcher and bindings to user defaults.

This is a big change that was hard to split into smaller commits. There’s now
a new class to bind shortcuts to actions, a new class to bind user defaults’
keys to actions, and a new way to associate user defaults with the recorder
control (MASShortcutView). I have also updated the demo app to go with the
changes.

The new class to associate shortcuts with actions is called MASShortcutMonitor.
It wraps the Carbon hotkey magic and offers a simple interface to add a
shortcut along with a block that should be run when the shortcut is pressed.
It’s the lowest-level interface.

Since the usual requirement is to store the shortcuts into user defaults,
there’s also a higher-level interface offered by the MASShortcutBinder class.
That takes a defaults key and associates it with a block. When the shortcut
stored under the defaults key changes, the binder automatically switches to the
new shortcut. The class is a wrapper built atop of the previous one, the
MASShortcutMonitor – it simply adds, updates and removes shortcuts as the
user defaults change.

I have removed the special user defaults integration code from the recorder
control (MASShortcutView) and replaced it with a small Cocoa Bindings shim.
This means that in order to keep the recorder control in sync with the defaults
you just have to call the usual bind:toObject:withKeyPath:options: method,
like this:

[_shortcutView bind:MASShortcutBinding
    toObject:[NSUserDefaultsController sharedUserDefaultsController]
    withKeyPath[@"values.ExampleDefaultsKey"
    options:@{NSValueTransformerNameBindingOption:NSKeyedUnarchiveFromDataTransformerName}];

That’s more verbose than the previous solution, but it’s much cleaner and can
be swept under a convenience call if needed. I might also add a dictionaryValue
property later that would make it possible to bind the value to user defaults
directly, without a transformer, and would enable backward compatibility with
Shortcut Recorder.
Removed explicit @synthesize and renamed “appearance” to “style”.

The “appearance” property didn’t play nice with auto-synthesizing,
not really sure why.
Turned MASShortcutMonitor into a singleton.

There can only be one Carbon event handler, so it doesn’t make sense
to create multiple instances of the shortcut monitor.