Blender Git Loki

File Browser: Keep file name after changing directory

Actually this was an intentional change in rBaeeb23efa28dc to prevent Blender from trying to open the old file from the new directory. Issue is that this is really bad for saving and basically breaks "Save As".

Some more tweaks were needed to make it work like before, so now it keeps the name of the last selected file, but clears it when selecting a folder.