Version.h held mostly stuff for protocol.h, which is a hub-specific file.
The only thing that we actually use is the PROTOCOL_VERSION in our code
and as such that one moved to the interfaces dir.
Merkle-block and merkle-tree classes and methods are pretty much stand-
alone and can be moved with no efforts.
Also move the relevent unit test to qtestlib.
tomFlowee
TomZ