Added _BaseSIPURI_to_pjsip_sip_uri to sipsimple/core.util.pxi

Ignore-this: b3654ab844b096e474f2e85a2892768b

darcs-hash:20090623102638-1e3d8-d3cf422e0414e339a35c8e62e2ab0b991a21c15d