Added fix for bug # 219

The vim state now has a initial selected range member. It is used when in visual mode to know when moving up or down to add or subtract to the start or end of the selected range. 
If visual mode is not active when moving up or down, the code executes the original call to editor.selectup/down 
It looks like the body of this conditional is the same as the other one, except with `--` replaced by `++`. Maybe it'd make sense to abstract out to a method within `MoveVertically`?