[Patch]Added support for the ofForceShowHidden flag in dialog options for Windows

Original Reporter info from Mantis: SergeAnvarov @SergeAnvarov

• Reporter name: Serge Anvarov

Description:

Before patch: option ofForceShowHidden is ignored
After patch: when ofForceShowHidden in options in open/save dialogs then hidden and system files are displayed

Steps to reproduce:

In the OpenDialog set the ofForceShowHidden in the Options and call Execute

Mantis conversion info:

• Mantis ID: 35452
• OS: Windows
• Platform: Windows
• Version: 2.1 (SVN)
• Fixed in revision: r61113 (#a897a24a)