bitcoin-cli: remove unneeded dependencies (only code movement)

Remove unnecessary dependencies for bitcoin-cli
(leveldb, berkelydb, wallet, RPC server)

Build system changes:
- split libbitcoin.a into libbitcoin_common.a, libbitcoin_server.a and
  libbitcoin_cli.a

Code changes (movement only):
- split up HelpMessage into HelpMessage in init.cpp and HelpMessageCli
  in rpcclient.cpp
- move uiInterface from init.cpp to util.cpp

src/test/test_bitcoin.cpp

@@ -14,7 +14,6 @@
 
 
 CWallet* pwalletMain;
-CClientUIInterface uiInterface;
 
 extern bool fPrintToConsole;
 extern void noui_connect();