Refactored some test code and tweaked SVG output

- Moves more file IO code into shared helpers
- Fixes a scale bug with plots of parametric curves
- Split up SVG code into several functions, uses
  groups to isolate transforms
- Adds approximate TF plot over the TRC table plots
- Adds gamut diagram output

Change-Id: Ifad7049ae97e39514bd41a79f996463fcddf32b1
Reviewed-on: https://skia-review.googlesource.com/111482
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
4 files changed