Merge branch 'master' into cycles_split_kernel

Cycles: Fix building of CUDA split kernel

Cycles: Fix indentation

Cycles: Fix strict warning about unused variable

Cycles: Calculate size of split state buffer kernel side

By calculating the size of the state buffer in the kernel rather than the host
less code is needed and the size actually reflects the requested features.

Will also be a little faster in some cases because of larger global work size.

Cycles: Fix crash after failed kernel build

Pointers to kernels were uninitialized leading to freeing of random memory
addresses. Another reason it would be good to use smart pointers.

Cycles: Faster building of split kernel

Simple change to make it so that only kernels that have been modified are
rebuilt. Might only be useful during development.

Cycles: Initialize rng_state for split kernel

Because the split kernel can render multiple samples in parallel it is
necessary to have everything initialized before rendering of any samples
begins. The code that normally handles initialization of
`rng_state` (`kernel_path_trace_setup()`) only does so for the first sample,
which was causing artifacts in the split kernel due to uninitialized
`rng_state` for some samples.

Note that because the split kernel can render samples in parallel this
means that the split kernel is incompatible with the LCG.

Cycles: Remove sum_all_radiance kernel

This was only needed for the previous implementation of parallel samples. As
we don't have that any more it can be removed.

Real reason for removal tho is this: `per_sample_output_buffers` was being
calculated too small and artifacts resulted. The tile buffer is already
the correct size and calculating the size for `per_sample_output_buffers`
is a bit difficult with the current layout of the code. As
`per_sample_output_buffers` was only needed for `sum_all_radiance`,
removing that kernel and writing output to the tile buffer directly
fixes the artifacts.

Cycles: Split path initialization into own kernel

This makes it easier to initialize things correctly in the data_init kernel
before they are needed by path tracing.

Merge branch 'master' into cycles_split_kernel

Cycles: Round global size down rather than up to avoid setting too large

Cycles: Get passes size in more robust way

Cycles: Use correct index for sd_dl_shadow after removing ccl_fetch

Cycles: Remove ccl_fetch and SOA

Revert "Cycles: Faster version of driver workaround for OpenCL"

Was getting infrequent hangs, unfortunately we have to take the performance
hit of clFinish for now.

This reverts commit 122743e7f23f8df908bcd10322d39f951ebc83e2.

Cycles: Fix buffer offsets in split kernel

Was getting wrong renders with multiple devices.

Cycles: Remove all split kernel stuff from opencl.h

Cycles: Reenable debug tile size for viewport rendering

Not a problem now that split kernel global size is decoupled from tile size.

Cycles: Report device maximum allocation and detected global size