Support all posible formats for VBO data

[Alexey Ozeritskiy]

See: https://www.khronos.org/opengl/wiki/Vertex_Specification_Best_Practices

VBOs are quite flexible in how you use them. For instance, there are a number of ways you can represent vertex attribute data in VBOs:

(VVVV) (NNNN) (CCCC)
One option for using them would be, for each batch (draw call) allocate a separate VBO per vertex attribute. This is certainly possible. If you have vertex, normal, and color as vertex attributes, pictorially this is: (VVVV) (NNNN) (CCCC)
(VVVVNNNNCCCC)
Another approach is to store the vertex attribute blocks in a batch, one right after the other, in the same block and stuff them all in the same VBO. When specifying the vertex attributes via glVertexAttribPointer calls you'd pass byte offsets into the VBO to the ptr parameters. Pictorially, this is: (VVVVNNNNCCCC).
(VNCVNCVNCVNC)
Yet another approach is to interleave the vertex attributes for each vertex in a batch, and then store each of these interleaved vertex blocks sequentially, again combining all the vertex attributes into a single buffer. As before, you'd pass byte offsets into the VBO to the glVertexAttribPointer ptr parameters, but you'd also use the stride parameter to ensure each vertex attribute array access only touched elements for that attribute array. Pictorially, this option is: (VNCVNCVNCVNC)

Now we support only (VNCVNCVNCVNC) format.