WHY IS THIS CHANGE NEEDED?:
- a case in which x and y dimensions are unequal is better at revealing
  dimension storage/conversion issues

HOW DOES THE CHANGE SOLVE THE PROBLEM?:
- tile existing image to size x = 1800, y = 1200

WHAT SIDE EFFECTS DOES THIS CHANGE HAVE?:
- filenames have changed

EVIDENCE THAT COMMIT WORKS:
- doesn't seem to break existing tests, specifically test_image.py and test_tiler.py

WHY IS THIS CHANGE NEEDED?:
- need a TIFF image file to serve as a dummy image input for dummy image
  processing functions

HOW DOES THE CHANGE SOLVE THE PROBLEM?:
- add TIFF file from unit test (staffa:560)

REFERENCES:
- issue #53

Relates to #52

Former-commit-id: 2b17ee6a922e2103a398fa3f5e6e23de1075fb96

Former-commit-id: 184f18f71b1d0ce12f1ef25e4a3a9b040f3cd828

Gaussian Process currently fixed to growth rate, could be used for
any signal in theory so the names might be changed later.
Also edited the processor so it can deal with a process that returns
multiple signals.


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