Tests for GimpGradientFile and a sample .ggr by me
Add (failing) test for GIMP 1.3 gradient files and .ggr by me
Fix for GIMP 1.3 gradient files
flake8
Test GimpGradientFile.sine()
Fix for Python 3
Remove duplicate tag caused by typo in spec: http://www.asmail.be/msg0055321032.html
flake8
Refactor inheritance tree of test_file_libtiff_small
Merge pull request #872 from wiredfool/test_libtiff_inheritance

Refactor inheritance tree of test_file_libtiff_small
Additional dependencies [ci skip]
Correct duplicate EXIF tags: http://www.exiv2.org/tags.html
flake8
Correct the correction: RelatedImageWidth=0x1001, RelatedImageLength=0x1002
Fail fast: move installation stuff that's not needed in the script: section closer to where it's needed. This saves time by avoiding it when a test fails.
Add access functions for ImagingEffectNoise with a test
test_effect_noise stalls on Travis, skip unless Windows
Remove unreachable and never completed Perlin turbulence code
Add access functions for ImagingEffectMandelbrot with a test
Add access functions for ImagingEffectSpread with a test