Merge pull request #643 from bvssvni/master

Reexported dot
Merge pull request #644 from bvssvni/master

Added perp
Merge pull request #647 from bvssvni/master

Reexported `add` and `sub`
Merge pull request #654 from bvssvni/master

Reexported functions
Merge pull request #656 from bvssvni/master

Reexported `vec2_mul_scalar`
Merge pull request #657 from bvssvni/master

Improved readability in deform