1) Added several interfaces to allow for easier extension and modification
2) Tracking of file transfer meta parameters
3) Default implementation forces proxy transfer to be associated with a file transfer negotiation that occured in the system

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@3762 b35dd754-fafc-0310-a699-88a17e54d16e