wxFD_PREVIEW implementation for wxGTK (slightly modified patch 1520690)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@40292 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -244,6 +244,7 @@ wxGTK:
 - Support underlined fonts in wxTextCtrl.
 - Support all border styles; wxListBox honours the borders now.
 - wxWindow and wxScrolledWindow now generate line, page and thumb-release scroll events.
+- Added file preview support in file dialogs.
 
 wxMac:
 

docs/latex/wx/filedlg.tex

@@ -23,6 +23,7 @@ This class represents the file chooser dialog.
 \twocolitem{{\windowstyle wxFD\_FILE\_MUST\_EXIST}}{For open dialog only: the user may only select files that actually exist.}
 \twocolitem{{\windowstyle wxFD\_MULTIPLE}}{For open dialog only: allows selecting multiple files.}
 \twocolitem{{\windowstyle wxFD\_CHANGE\_DIR}}{Change the current working directory to the directory where the file(s) chosen by the user are.}
+\twocolitem{{\windowstyle wxFD\_PREVIEW}}{Show the preview of the selected files (currently only supported by wxGTK using GTK+ 2.4 or later).}
 \end{twocollist}
 
 {\bf NB:} Previous versions of wxWidgets used {\tt wxFD\_CHANGE\_DIR} by default