Renamed Icon payload definition to PresenceContent

Ignore-this: 51bc87e54b6309701d345655b8526145

darcs-hash:20100831135732-1e3d8-bcb1f733b01dad0e57323f6a70be03419824dbc9
Added extension to add a display-name to common policy rules

Ignore-this: 686bef0703cc894dfb9c36a4015bba22

darcs-hash:20100831135847-1e3d8-d2c03c56e88cd48a89a0774349a93359a1f963df