Replaced all occurrences of #if* __WXMSW__ with WIN32,
and all occurrences of __WXMAC_OSX__ with MAC_OSX, and made
sure those are defined appropriately in the makefile and bitcoin-qt.pro.
Makefiles now build bitcoind only.
qmake/make in top-level directory is used to build Bitcoin QT
Deleted almost all #ifdef GUI from the code (left one possibly controversial one)
Deleted xpm/ files.
This introduces two new source files, keystore.cpp and wallet.cpp with
corresponding headers. Code is moved from main and db, in a preparation
for a follow-up commit which introduces the classes CWallet and CKeyStore.