Add convenience methods to specify Buffer data from a plain struct

[j-o]

This simplifies data upload to buffers containing control structures (e.g., uniform buffers) Example:

struct UniformBufferData
{
    glm::mat viewProjection;
    glm::vec2 viewport;
    float viewport;
};

auto data = UniformBufferData{ ... };
myBuffer->setData(data, GL_STATIC_DRAW); // new
myBuffer->setData(sizeof(UniformBufferData), &data, GL_STATIC_DRAW); // old