Change directory to current folder when no project files are found
Sometimes I want to edit a single file which is not in a project. In previous stable release (v1.5.0), the working directory is the folder where this file locates in. But in the new stable release (v1.6.0), the working directory becomes the folder where `Spacevim` configuration files locate in.

So is it possible to add an option that allow vim to change its working directory to current folder when no project files are found? 