update CClientUIInterface and remove orphan Wx stuff

- fix ThreadSafeMessageBox always displays error icon
- allow to specify MSG_ERROR / MSG_WARNING or MSG_INFORMATION without a
  custom caption / title
- allow to specify CClientUIInterface::ICON_ERROR / ICON_WARNING and
  ICON_INFORMATION (which is default) as message box icon
- remove CClientUIInterface::OK from ThreadSafeMessageBox-calls, as
  the OK button will be set as default, if none is specified
- prepend "Bitcoin - " to used captions
- rename BitcoinGUI::error() -> BitcoinGUI::message() and add function
  documentation
- change all style parameters and enum flags to unsigned
- update code to use that new API

- update Client- and WalletModel to use new BitcoinGUI::message() and
  rename the classes error() method into message()
- include the possibility to supply the wanted icon for messages from
  Client- and WalletModel via "style" parameter

src/ui_interface.h

@@ -29,38 +29,46 @@ public:
     /** Flags for CClientUIInterface::ThreadSafeMessageBox */
     enum MessageBoxFlags
     {
-        YES                   = 0x00000002,
-        OK                    = 0x00000004,
-        NO                    = 0x00000008,
-        YES_NO                = (YES|NO),
-        CANCEL                = 0x00000010,
-        APPLY                 = 0x00000020,
-        CLOSE                 = 0x00000040,
-        OK_DEFAULT            = 0x00000000,
-        YES_DEFAULT           = 0x00000000,
-        NO_DEFAULT            = 0x00000080,
-        CANCEL_DEFAULT        = 0x80000000,
-        ICON_EXCLAMATION      = 0x00000100,
-        ICON_HAND             = 0x00000200,
-        ICON_WARNING          = ICON_EXCLAMATION,
-        ICON_ERROR            = ICON_HAND,
-        ICON_QUESTION         = 0x00000400,
-        ICON_INFORMATION      = 0x00000800,
-        ICON_STOP             = ICON_HAND,
-        ICON_ASTERISK         = ICON_INFORMATION,
-        ICON_MASK             = (0x00000100|0x00000200|0x00000400|0x00000800),
-        FORWARD               = 0x00001000,
-        BACKWARD              = 0x00002000,
-        RESET                 = 0x00004000,
-        HELP                  = 0x00008000,
-        MORE                  = 0x00010000,
-        SETUP                 = 0x00020000,
-        // Force blocking, modal message box dialog (not just OS notification)
-        MODAL                 = 0x00040000
+        ICON_INFORMATION    = 0,
+        ICON_WARNING        = (1U << 0),
+        ICON_ERROR          = (1U << 1),
+        /**
+         * Mask of all available icons in CClientUIInterface::MessageBoxFlags
+         * This needs to be updated, when icons are changed there!
+         */
+        ICON_MASK = (ICON_INFORMATION | ICON_WARNING | ICON_ERROR),
+
+        /** These values are taken from qmessagebox.h "enum StandardButton" to be directly usable */
+        BTN_OK      = 0x00000400U, // QMessageBox::Ok
+        BTN_YES     = 0x00004000U, // QMessageBox::Yes
+        BTN_NO      = 0x00010000U, // QMessageBox::No
+        BTN_ABORT   = 0x00040000U, // QMessageBox::Abort
+        BTN_RETRY   = 0x00080000U, // QMessageBox::Retry
+        BTN_IGNORE  = 0x00100000U, // QMessageBox::Ignore
+        BTN_CLOSE   = 0x00200000U, // QMessageBox::Close
+        BTN_CANCEL  = 0x00400000U, // QMessageBox::Cancel
+        BTN_DISCARD = 0x00800000U, // QMessageBox::Discard
+        BTN_HELP    = 0x01000000U, // QMessageBox::Help
+        BTN_APPLY   = 0x02000000U, // QMessageBox::Apply
+        BTN_RESET   = 0x04000000U, // QMessageBox::Reset
+        /**
+         * Mask of all available buttons in CClientUIInterface::MessageBoxFlags
+         * This needs to be updated, when buttons are changed there!
+         */
+        BTN_MASK = (BTN_OK | BTN_YES | BTN_NO | BTN_ABORT | BTN_RETRY | BTN_IGNORE |
+                    BTN_CLOSE | BTN_CANCEL | BTN_DISCARD | BTN_HELP | BTN_APPLY | BTN_RESET),
+
+        /** Force blocking, modal message box dialog (not just OS notification) */
+        MODAL               = 0x10000000U,
+
+        /** Predefined combinations for certain default usage cases */
+        MSG_INFORMATION = (ICON_INFORMATION | BTN_OK),
+        MSG_WARNING = (ICON_WARNING | BTN_OK | MODAL),
+        MSG_ERROR = (ICON_ERROR | BTN_OK | MODAL)
     };
 
     /** Show message box. */
-    boost::signals2::signal<void (const std::string& message, const std::string& caption, int style)> ThreadSafeMessageBox;
+    boost::signals2::signal<void (const std::string& message, const std::string& caption, unsigned int style)> ThreadSafeMessageBox;
 
     /** Ask the user whether they want to pay a fee or not. */
     boost::signals2::signal<bool (int64 nFeeRequired, const std::string& strCaption), boost::signals2::last_value<bool> > ThreadSafeAskFee;