Generate and process errors on alarm/alert restoration.

Errors are used in a somewhat nonstandard fashion in places: partially restored (yet valid) objects are returned, along with an error.

We're still using a mixture of exceptions and errors here, united by Wolf Rentzsch's JRErr.  Eventually the NSAsserts should be replaced by something better, though still exceptions.

Rename -[PSAlarm resetTimer] to -[PSAlarm restoreTimer]; the previous name was technically correct but confusing; the current one is also consistent with usage in PSAlarms.

Add tests for alarm/alert restoration.

Fix some wording when describing what to do when no alerts are enabled.  (This should logically have been a separate change.)
Remove a non-ASCII character from source.
Update Sparkle.
Add a workspace since Xcode 4 wants to put one there.

Ignore shareddata (some Git URLs that may or may not be correct for you).
Share a Pester scheme which lets you both build and test.