Remove singular workspaces check

Singular workspaces check introduced in #25 no longer necessary,
as mm_workspace setting is automatically dropped into an array

This check causes the workspaces array to be put in a new array, 
meaning the fs.existsSync call fails, as it's being passed an array
instead of the workspace path. As such, have removed the check
and adjustment

Hopefully this isn't any issue that's just peculiar to my install :D