Add a few more options to FileBrowser toolslib control

[RobertoBozzolo]

I'd like the following options being added to FileBrowser tollslib control:

• Ability to hide / tailor popup menu for the right portion of the FileBrowser (file list): at present, even if I disable the popup menu on the tree control (regardless it is made before or after converting the tree into a FileBrowser) the rightmost part of the control has its own popup menu enabled
• In case the menu is shown, it would be a good thing to be able to add / change / hide items in that menu
• Ability to programmatically set the width of columns in the file list section of the FileBrowser
• Ability to programmatically set the label of columns both sections of the FileBrowser: this is particularly necessary in case you need to localize the user interface in a language other than English, as FileBrowser cannot be treated by the Localization Utility since it is created at runtime