Description of the Issue

Support of unix path separator "/" in addition to windows back slash ""

Steps to Reproduce the Issue

1. I pasted the following path into the "open file" => "filename" window: "C:/liferay/portal-setup-wizard.properties".
2. Got the error message "filename is not valid" (my translation as I am using a german version)

Expected Behavior

Opening the file from "C:\liferay\portal-setup-wizard.properties"

Actual Behavior

Popup with error message (see above)

Debug Information

Notepad++ v6.9.2
Build time : May 18 2016 - 00:34:05
Path : C:\Program Files (x86)\Notepad++\notepad++.exe
Admin mode : OFF
Local Conf mode : OFF
OS : Windows 7
Plugins : Explorer.dll HTMLTag_unicode.dll mimeTools.dll NppConverter.dll NppExport.dll NppFTP.dll NppTextFX.dll PluginManager.dll XMLTools.dll