Use max value for all trailing palette entries

Otherwise, if the non-last has a max value, the ones after it can go
beyond the allowed range. Fixes #95.
8 jobs for master in 3 minutes and 56 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build
passed build-debian #5077
debian amd64

00:00:30

passed build-debian-aarch64 #5081
aarch64 debian

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passed build-debian-aarch64-clang-5 #5082
aarch64 clang5 debian

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passed build-debian-static #5078
debian amd64

00:00:30

passed build-debian-werror #5084
debian

00:01:13

passed build-macos #5083
macos

00:00:28

passed build-win32 #5079
win32

00:00:27

passed build-win64 #5080
win64

00:00:32