Store Client ID and API key in the user keychain and reuse the status bar item and menu

Hi,

  I have made a couple of small changes to the code to store the client ID and API key in the user keychain instead of as plain text in the userdefaults.  I have also added code to show the preferences window by default if there are no details entered.  Refreshing now also reuses the status bar item and the NSMenu attached to it.

Daniel