Fixed classproperty usage

Ignore-this: 8160af0b8b630ea725a5c2e4c6beb689

darcs-hash:20100831091116-56b4d-9d0a201bb112d5ad1d489a816099f51ab2f8a261
Added support for MWI

Ignore-this: cfa9ea0c01c34f48876fac78225cda16

darcs-hash:20100831114745-56b4d-34fcdf9e1b1766f177db9ad3c761cc7af2cb2eb3