Small changes to Matrix4 and Vector3
Also add clamp to Vector and Vector2
Fix typo
Fix typo #2
Fix typo #3
Remove Vector#mul/#div, add Vector#scl and some other small changes.
Handle division by zero
Add Matrix4#setTranslation and some minor changes to Matrix4
Merge pull request #275 from xoppa/math

Small changes to Matrix4 and Vector3