Revision history for Sentinel

0.04    CHANGES:
         * Detect at Build.PL time whether XS is possible, don't attempt if
           not. Also allow PP building with --pp argument

0.03    CHANGES:
         * Provide a fallback pureperl implementation using TIESCALAR if XS
           cannot be loaded (thanks mst)
         * More unit tests

0.02    CHANGES:
         * Non-development release

0.01_004 CHANGES:
         * Apply some evil SvFLAGS hackery on perl versions before 5.14 to
           make lvalue context propagation work correctly

0.01_003 CHANGES:
         * Discovered that true lvalue context propagation does work on
           perl 5.14 - document this and unit test it

0.01_002 CHANGES:
         * Support 'obj' for referent object context to callbacks
         * Minor XS logic fixes

0.01_001 First version, released on an unsuspecting world.