Global settings override cause conflicts with vim configuration and/or other plugins

Hello,

There is a configuration part marked as "optional", it contains some commands that override global vim settings. 

For example, I like having ```foldmethod = marker```, but after I open any markdown file whole vim is set to ```foldmethod = expr``` instead.

I removed those global overrides as they are the most painful for me, however I suggest to consider cleaning up the whole "optional" section, maybe make a documentation note instead.