Updates to Coherence Tutorial Based on Steve's Review

[joferkington]

Here's the rest of my changes to the tutorial based on Steve Purves's comments (and several other minor fixes).

Major changes:

1. Added discussion of bleed-through and other trade-offs with window size changes
2. Added acknowledgments section
3. Fixed mistake in Gerzstenkorn explanation figures due to typo in figure-generating code
4. Made all figures larger

Thanks!