Metacello 1.0-beta.28.3.1 released

Targeted at Pharo1.2

- fix Issue 3758: Metacello has 12 failing tests in 1.2
  http://code.google.com/p/pharo/issues/detail?id=3758
- well ... add expectedFails for the tests are failing due to the fix
for Pharo Issue 3660

Dale