Bulked up fixes to the release

[zenangst]

The picking of configuration looks like this now:

• Fix cache identifiers
• Expose run on CommandEngine
• Move the keyboard engine error definitions outside of the class
• Move the apple script plugin error definitions outside of the class
• Set notification default to false on KeyboardCommand
• Set defaults for ScriptCommand's
• Set notification default to false on TypeCommand
• Add editor command to the default configuration (either Xcode or TextEdit)
• Add additional application commands (Terminal, Safari) to the default configuration
• Add example Apple Script command to show how to use Apple Script to open a specific
  note in the Notes.app
• Add additional open commands (Documents, Downloads)
• Add rebinding commands to add Vim binding navigation
• Add imdb.com url command
• Add type command that is scoped to Mail to add a mail signature
• Add support for running commands in the DetailCommandActionReducer
• Implement basic error handling when running commands using the DetailCommandActionReducer
  by forwarding the errors to NSAlert
• Add new UI for the "pick configuration" screen
• Pass the same namespace between loading and pick-configuration view
  for a nice transition between states
• Fix visual bugs and nit-picky design improvements in the content list
• Fix bug with using .focusSection in the EditableKeyboardShortcutView
• Remove redundant .onAppear implementation in the GroupsListView

Reference: #243