Added french UI translation.
- BUGFIX : [MainForm.cs] Check if _mainDockPanel.GetActiveDocument() isn't Null reference before closing
- BUGFIX : [MainForm.cs] Check if documents are opened before prompt user to close
- ADDED : [InternationalSettingsEditor.cs,english.xml,french.xml] translation ItemGroup and Key/Value
Revert "- BUGFIX : [MainForm.cs] Check if _mainDockPanel.GetActiveDocument() isn't Null reference before closing"

This reverts commit 81bf305309d4c14498c70e2280e75236512b5126.
Merge pull request #4 from wallace87000/master

Added french UI translation.