OpenCL fast tiling fix plus maintenance

[jenshannoschwalm]

1. The OpenCL fast tiling code had two bugs now fixed
   a) the per line requirements for tiling were calculated too small leading to larger tile sizes than allowed
   b) the aligning of tile sizes was wrong leading to bad overlaps (this could be seen in 0153 integration test having much larger CPU/GPU diffs)
2. Some maintenance and subtle perf improvements
   a) some constify
   b) more use of readpixel() variants - in some cases using the faster Aread.. variant
   c) more use of dtcl_xxx macros

[jenshannoschwalm]

@TurboGit integrations tests all good :-)

BTW - we have some subtle new CPU diffs after @kofa did the math fixing for color/tone equalizers.

[TurboGit]

BTW - we have some subtle new CPU diffs after @kofa did the math fixing for color/tone equalizers.

Number of pixel diff, right?

[jenshannoschwalm]

Number of pixel diff, right?

      Expected CPU vs. current CPU report :
      ----------------------------------
      Max dE                   : 2.20445
      Avg dE                   : 0.00012
      Std dE                   : 0.00886
      ----------------------------------
      Pixels below avg + 0 std : 99.98 %
      Pixels below avg + 1 std : 99.98 %
      Pixels below avg + 3 std : 99.98 %
      Pixels below avg + 6 std : 99.98 %
      Pixels below avg + 9 std : 99.98 %
      ----------------------------------
      Pixels above tolerance   : 0.00 %

[TurboGit]

Right, we had:

Test 0159-coloreq-guided-filter
      Image mire1.cr2
      Expected CPU vs. current CPU report :
      ----------------------------------
      Max dE                   : 1.13387
      Avg dE                   : 0.00333
      Std dE                   : 0.03597
      ----------------------------------
      Pixels below avg + 0 std : 98.99 %
      Pixels below avg + 1 std : 99.00 %
      Pixels below avg + 3 std : 99.06 %
      Pixels below avg + 6 std : 99.14 %
      Pixels below avg + 9 std : 99.50 %
      ----------------------------------
      Pixels above tolerance   : 0.00 %

So a bit worst now.

[TurboGit]

Thanks!