Renderpass can now exist without Framebuffer, fix the clear to account for this
Renderpass can now exist without Framebuffer, fix the clear to account for this

turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo,turol/smaaDemo