Removed obsolete desktop sharing files

Ignore-this: e7d0b3223c4c2f83d44fb05029949fcf

darcs-hash:20091106130114-b22ec-87acff1d7180cae94b9dcbc561198b6a195003ba
Changed default user_agent to sipsimple instead of sip2sip

darcs-hash:20091112085901-58252-4758b415e050a19911572882f79b0d6e699951da