Fixing scaling and position of horizontal scrollbar when scaling left

[RobLoach]

@MikemathuKE @dumblob Cherry picked the commits in, but am in no way qualified to test this.

Fixes #219

[dumblob]

LGTM

Maybe what about adding a comment to the source code about the "priority" problem? Quoting @MikemathuKE:

Unfortunately, I could not scale since the horizontal scrollbar was given priority. Therefore I fixed it by moving the position of the horizontal scrollbar so that it doesn't overlap with the scaler.

[dumblob]

@RobLoach do you think the (currently missing :wink:) comment would make it clear?

[RobLoach]

I have no context into the issue or what could improve it. :shrug:

[dumblob]

LGTM. Let's bump the version and merge!