Minor fixes
Add new test image snake.pnm
Update tests
Merge branch 'coverage' into release-0.20
Merge branch 'release-0.20' into release
Merge branch 'release' into develop
Merge branch 'release'
Update coverage status badge
Merge branch 'develop'
Support to load bitmap v5 header
Add a bmp v5 test image
Merge branch 'sandbox' into fix-for-loading-bmp-v5
Add TGA/TIFF test images
Merge branch 'fix-for-lacking-getopt_long' into feature-long-option
Merge branch 'master' into release
Merge branch 'stb_image' into release-0.21
Merge branch 'feature-long-option' into release-0.21
Merge branch 'fix-for-loading-bmp-v5' into release-0.21
Bump version
Rebuild configure script