fix -datadir=./subdir relative path,

autostart off by default except on windows,
fix occasional "vector iterator not dereferencable" assertion with msvc,
fix readlink compile warning on linux build,
use sys/param.h and BSD define instead of __BSD__,
-paytxfee switch

main.cpp

@@ -2224,7 +2224,7 @@ bool ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         // This includes all nodes that are currently online,
         // since they rebroadcast an addr every 24 hours
         pfrom->vAddrToSend.clear();
-        int64 nSince = GetAdjustedTime() - 24 * 60 * 60; // in the last 24 hours
+        int64 nSince = GetAdjustedTime() - 12 * 60 * 60; // in the last 12 hours
         CRITICAL_BLOCK(cs_mapAddresses)
         {
             unsigned int nSize = mapAddresses.size();