Render to framebuffer Target, then blit to swapchain

[MrBrixican]

• Render to framebuffer Target, then blit to swapchain
• Fixed depth for Texture, should be 1
• Mailbox, Immediate present mode issues fixed
• Fixed frame stuttering on excessive cycle flushing

[MrBrixican]

Oh, I forgot this also includes some changes to the way buffers are initially sized. Exactly sized buffers are created upon first data upload and then next power of two is used. I can remove this logic if it's too much for this PR, though.

[NoelFB]

I think that all makes sense! Thanks! :)