Use consistent type for native arrays

[w0rm]

I noticed that MJS.js defines var MJS_FLOAT_ARRAY_TYPE = Float64Array; while Vector2.js and Vector4.js use var MJS_FLOAT_ARRAY_TYPE = Float32Array;

I don't know if this was intentional or not, but I think this library should use the same type for all.

cc @felixLam

[fredcy]

The change from 32 to 64 in MJS.js broke some WebGL apps (as you know). Is there a similar concern here? How can we test the impact of the change proposed here?

[w0rm]

@fredcy the fix was applied to the uniforms of all linear algebra types, not just Mat4: elm-community/webgl@e769047

[fredcy]

I will gladly entertain a PR for this issue.

[w0rm]

I looked into this again, and I think it is better to use Float32Array because in the end this is what is used WebGL. threejs even has a warning for this