x11-themes: add numix-icon-theme
Add ~x86 to PLATFORMS

I don't use x86, but there is no reason to fail for any of these
packages.
Add KindleGen-EULA licence
app-text: add kindlegen
dev-ruby: add mustache
rcm: fix scm, remove broken mask
dev-util: add cram
rcm: add dev-util/cram as test dep