NotifyBlockTip signal: switch from hash (uint256) to CBlockIndex*

- also adds a boolean for indication if the tip update was happening during initial sync
- emit notification also during initial sync

src/ui_interface.h

@@ -15,6 +15,7 @@
 class CBasicKeyStore;
 class CWallet;
 class uint256;
+class CBlockIndex;
 
 /** General change type (added, updated, removed). */
 enum ChangeType
@@ -94,7 +95,7 @@ public:
     boost::signals2::signal<void (const std::string &title, int nProgress)> ShowProgress;
 
     /** New block has been accepted */
-    boost::signals2::signal<void (const uint256& hash)> NotifyBlockTip;
+    boost::signals2::signal<void (bool, const CBlockIndex *)> NotifyBlockTip;
 
     /** Banlist did change. */
     boost::signals2::signal<void (void)> BannedListChanged;