shift "Chosing an Editor" down in Readme.md (and thus priority)

[kloimhardt]

This is a highly subjective PR: I think the "Choosing an Editor" section in Readme.md should be shifted downwards.

Explanation: The value proposition of Clerk is that any editor can be used, even Notepad++. Thus I suggest to remove "Choose an Editor" from the strictly necessary steps of "Running / Editing the Essays".