Alternating solver for intensity correction

[minnerbe]

In the spirit of the alternating solver for alignment (see #160), I added a similar solver for intensity correction. It works in exactly the same way as the analogue for alignment, but two changes to the existing code were necessary:

• The rendering method that is used to match intensities between tiles didn't take into account existing intensity filters. It does now. I put this into Render.render rather than VisualizeTools.getUntransformedProcessorWithMasks to preserve my notion of "untransformed" (meaning also no filters).
• A LinearIntensityMap8BitFilter can now absorb a second filter to emulate chaining of linear functions.

Results

I tested the implementation on one layer of wafer_53 with a 3x3 XY-block layout; see pictures below.
While I can still see some tile boundaries after one run, the results after two runs look qualitatively very close to the baseline (intensity correction without blocks).

• Original layer:
• Reference IC (no blocks):
• One run of blocked IC:
• Two consecutive runs of blocked IC:

[trautmane]

looks great!