Merge pull request #3412

c3a7f51 Move `verifymessage` from rpcwallet to rpcmisc (Wladimir J. van der Laan)
723a03d Move `createmultisig` from rpcwallet to rpcmisc (Wladimir J. van der Laan)
452955f Move `validateaddress` from rpcwallet to rpcmisc (Wladimir J. van der Laan)
cd7fa8b Move `nTransactionFee` from main.cpp to wallet.cpp (Wladimir J. van der Laan)
a943bde Move `settxfee` from rpcblockchain to rpcwallet (Wladimir J. van der Laan)
16bc9aa Move `getinfo` from rpcnet to rpcmisc (Wladimir J. van der Laan)
652e156 add new RPC implementation file `rpcmisc.cpp` (Wladimir J. van der Laan)
Make bitcoin compile without wallet if "db_cxx.h" is not present

Moved includes of "db.h" into #ifdef ENABLE_WALLET blocks or remove
them.
qt: Make sure overviewpage button is pressed at startup

Due to walletframe changes, the overview page button is no longer
automatically selected at startup even though the overview page is shown.