Raised core revision

Ignore-this: 451d98a32aea93de521aa6fed0311238

darcs-hash:20130304103207-56b4d-15a7d4a53536ac6d9c8b149cfe58c8f2b48eb7d7
Define __nonzero__ for XCAP Document objects

Ignore-this: c4db790f2e51aa972a2b9d32cd0f1ad6

darcs-hash:20130314172801-56b4d-8e456375abae67010a9eecd032d2a97f8270b3f8