Add Dependency_CustomExecute define

Closes #80

Author: DomGries

CodeDependencies.iss

@@ -101,7 +101,11 @@ begin
 
         while True do begin
           ResultCode := 0;
+#ifdef Dependency_CustomExecute
+          if {#Dependency_CustomExecute}(ExpandConstant('{tmp}{\}') + Dependency_List[DependencyIndex].Filename, Dependency_List[DependencyIndex].Parameters, ResultCode) then begin
+#else
           if ShellExec('', ExpandConstant('{tmp}{\}') + Dependency_List[DependencyIndex].Filename, Dependency_List[DependencyIndex].Parameters, '', SW_SHOWNORMAL, ewWaitUntilTerminated, ResultCode) then begin
+#endif
             if Dependency_List[DependencyIndex].RestartAfter then begin
               if DependencyIndex = DependencyCount - 1 then begin
                 Dependency_NeedToRestart := True;