Vector methods are extended to receive vectors as individual numbers
for each of x,y,z,w component. The vector objects are still supported
as well.
Previously only single value scalar was supported. This change maintains
backward compatibility.
```
v = vec3():add( 1, 2, 3 ) -- both do the same
v = vec3():add( vec3(1, 2, 3) ) _/
v = vec4():mul( 2 ) -- x component is a default for y, z
v = vec4():mul( 2, 2, 2, 2 ) _/
v = vec2():lerp( 2, 2, 0.5 ) -- in lerp, dot, cross, distance
v = vec2():lerp( vec2(2, 2), 0.5 ) _/ all components are mandatory
```
lookAt() returns view matrix that can be used to transform the camera
perspective. target() returns model matrix that is used to change
model transform. Results are matrix inversions of one another. Now both
functions exist it is possible to use right one and avoid extra matrix
inversion.