Fixed typo in sipsimple/core.headers.pxi

Ignore-this: 63ba2b40554a8ed16fb6da1136545628

darcs-hash:20090715142250-1e3d8-d3b9f03d39c93c6185b43149124e007080b17f29
Fixed typos in richcmp functions of header types

Ignore-this: 12139aa6d1a0ee46efca304b9c87df8e

darcs-hash:20090716112938-1e3d8-690ae2060f4b07f74d3b9fdc992c30468572edee