Fixing line intersection for lines through origin

[bcvery1]

Resolves #210

Description

The issue was that the algorithm which gets the closest corner of a Rect to a point on the line did not account for that point being ZV, so always ignored it. The algorithm now uses a pointer to ensure every closest vector is valid.

Changes

• Added tests to the closest point function to confirm vertical and horizontal lines work fine
• Added test as proposed in the issue to confirm the bug is fixed
• Replaced zero vector as the initial closest value with a pointer
• Updated change log

[delp]

Awesome, thanks for the quick turn around on this.