Vector class improvements

[Admer456]

The Vector class requires a few extra operators:

• [x] Vector += Vector
• [x] Vector -= Vector
• [x] Vector *= float
• [x] Vector /= float
• [x] Vector * Vector (which is a dot product)

And a few extra methods:

• [x] Reflect( normal, modifier ) - calculates a reflected vector, useful to calculate bouncing stuff
• [x] RotateAboutAxis( axis, angle ) (quaternions are better for this)
• [x] ProjectOnPlane( normal ) - projects this vector on a plane
• [x] AngleVectors( forward, right, *up ) - stores directional vectors into forward, right and up, assuming this is an angle vector
• [x] Equals( vec, epsilon ) - compares two vectors with epsilon tolerance
• [x] ToAngles() - converts this vector into an angle vector, taking into account the direction (roll is always 0)
• [ ] ToAngles( forward, right ) - converts this vector into an angle vector, works for roll as well

[Admer456]

I consider this done for now. Solved by commits d8b5a54885164bd629389bd92317f1ebd9d097e2 to cd6f86f4b8457f6c8da119d87e31c639355ff80e.