[Pharo-project] Cleanup of Deprecation

I just committed (with much help from Stéphane) my first contribution to Pharo! Cleanup of Deprecation Status: Fixed Owner: ---- Milestone-1.0 Submitted a bunch of small fixes that make the use of deprecation uniform across Pharo. The changes are mostly to the wording of the deprecation message. They also restore the previous behavior of the exception handler so that the notifier says that something has been deprecated. The package is Slice-CleaningDeprecation-AndrewBlack.1