Add support for timestamp encoding in exemplars #938

Job	Run time
Test Suite	1m 57s
Check	1m 41s
Rustfmt	24s
Clippy	1m 16s
Cross compile (armv7-unknown-linux-gnueabihf)	19s
Check rustdoc intra-doc links	29s
Cross compile (wasm32-unknown-unknown)	21s
Cross compile (powerpc-unknown-linux-gnu)	22s
Cross compile (powerpc64-unknown-linux-gnu)	21s
	7m 10s

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