Remove deprecated elements

[tharvik]

Some elements are tagged as Deprecated, we should remove theses in a next update.

Here goes a list of the ones tagged:

• SendTreeMsgID
• RequestRosterMsgID
• SendRosterMsgID
• OverlayMsg.{RequestRoster,Roster,TreeMarshal}
• Overlay.{TreeNodeFromToken,handleRequestTreeDeprecated,handleSendTreeMarshal,handleRequestRoster,handleSendRoster}
• TestRoster_ID\
• log.LinePadding
• TreeID.Equal
• Roster.ID
• network.ServerIdentity.ID

[ineiti]

This should be done in v4 - even though this means probably never for the moment :( Trading off 'it's not nice' against 'will break some code somewhere unforeseen', I choose the former...