Only send file for and outgoinf FileTransferStream

Ignore-this: 3d849e8af0ce8263bd1e0f9a1bd3cf8f

darcs-hash:20091017024916-b22ec-69d16839330e5b85652fbe2574d900d0c2e663e5
Use chunk instead of message in the FileTransferStream's notification data

Ignore-this: a6ed33bae62d60053206800c2c1819b6

darcs-hash:20091017033654-b22ec-afa603026b2b072a116ceff5509d52aec74a1dff