V8DebuggerClient: Enable breakpoints on Exceptions

Previously break on exceptions was always enabled. Now, the user
can add a breakpoint on Javascript Exceptions from the breakpoint
window in the debugger.

Change-Id: Ia9ee813d2fccf89b607fe1dcbad47b4084155a48
Reviewed-on: http://codereview.qt-project.org/6348
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>

src/plugins/debugger/breakhandler.cpp

@@ -124,6 +124,8 @@ static QString typeToString(BreakpointType type)
             return BreakHandler::tr("Watchpoint at Expression");
         case BreakpointOnQmlSignalHandler:
             return BreakHandler::tr("Breakpoint on QML Signal Handler");
+        case BreakpointAtJavaScriptThrow:
+            return BreakHandler::tr("Breakpoint at JavaScript throw");
         case UnknownType:
             break;
     }