gl: fix disembodied player model found in #141

[iceiix]

Regression introduced in #262 by the glow port, correct the raw size to
account for the matrix. See #141 (comment)

[iceiix]

Before:

After:

This works but there were subsequent changes to src/gl/mod.rs to remove "replace set_float_multi_raw with a safer set_float_multi", in #451 for WebGL

Broken code:

    #[allow(clippy::missing_safety_doc)]
     pub unsafe fn set_float_multi_raw(&self, data: *const f32, len: usize) {
         glow_context().uniform_4_f32_slice(Some(&self.0), std::slice::from_raw_parts(data, len));
     }

working code, but using unsafe raw pointers:

// src/render/model.rs
                    unsafe {
                        v.set_float_multi_raw(model.colors.as_ptr() as *const _, model.colors.len())
                    }

// src/gl/mod.rs
    #[allow(clippy::missing_safety_doc)]
     pub unsafe fn set_float_multi_raw(&self, data: *const f32, len: usize) {
         glow_context().uniform_4_f32_slice(Some(&self.0), std::slice::from_raw_parts(data, len * 4 * 4));
     }

broken code using slices:

// src/render/model.rs
                    v.set_float_multi(&model.colors)

// src/gl/mod.rs
    pub fn set_float_multi(&self, v: &[[f32; 4]]) {
        unsafe {
            glow_context()
                .uniform_4_f32_slice(Some(&self.0), &*(v as *const [[f32; 4]] as *const [f32; 4]))
        }
    }