Update the Hgfs server interface for tools

Update the Hgfs server interface for tools

The Hgfs server interface was redone to work with multiple transports
however the tools side was left fudged.
Now upgrade the tools side interfaces into the Hgfs server.
The server interface is now hidden within the HgfsServerManager library.
The tools clients of the HGFS server now use the HgfsServerManager
interfaces directly:
HgfsServerManager_DataInit
HgfsServerManager_Register
HgfsServerManager_Unregister
HgfsServerManager_ProcessPacket

An HgfsServerManager guest is now built into the hgfs library with the server
and other related HGFS library code. The Hgfs server guest does not do any
RPC handling now as the library would have required building with both RPC
libraries and as such the RPC registering and callbacks are pushed back into
the caller.
At some future point when only one RPC library is used and all callers are built
in the same way, the HGFS RPC calls can be pushed back into the
HGfsServerManagerGuest to remove duplication of code.

Signed-off-by: Marcelo Vanzin <mvanzin@vmware.com>