Don't scale the element border along with the element

[toolness]

This issue has been migrated from mozilla/webmaker-android#1761.

It was originally written by flukeout on Sun May 10 2015 and had the following description:

When you scale an element, like Tucker, the border scales with it so it stops looking like the dashed border that you saw in the beginning and just gets really thin. The selection border should appear the same no matter how big the element is.