removed unused imports and dead code

darcs-hash:20090128093035-b2873-4ef8cbec82748e1654f72c6270fe0c7679d8a7a4
sip_im_session.py: fix for ctrl-d closes 2 sessions at once

darcs-hash:20090128093100-b2873-9ac5b612f069935708cafafd53fdf6f58ea5f696