* FileName:

* FileName:
- introduce changeExtension(): the goal is to replace progressively the one in filetools.cpp
- get rid of internal_path() checking for Win32 as the path is always normalized with slashes with QFileInfo.

* BufferParams: get rid of filepath member. This was used only once and was fixing a path in BufferParam was wrong anyway.

* Buffer::filePath(): always regenerate instead of caching it in BufferParams.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@21847 a592a061-630c-0410-9148-cb99ea01b6c8