Add Counter app with gui #15

Job	Run time
nixbuild	6m 25s
build (stable, x86_64-unknown-linux-gnu, time)	52s
build (stable, x86_64-unknown-linux-gnu, timer)	47s
build (stable, x86_64-unknown-linux-gnu, counter)	3m 20s
build (stable, x86_64-pc-windows-msvc, time)	1m 58s
build (stable, x86_64-pc-windows-msvc, timer)	46s
build (stable, x86_64-pc-windows-msvc, counter)	4m 34s
build (stable, i686-pc-windows-msvc, time)	2m 15s
build (stable, i686-pc-windows-msvc, timer)	1m 35s
build (stable, i686-pc-windows-msvc, counter)	5m 33s
build (stable, x86_64-apple-darwin, time)	37s
build (stable, x86_64-apple-darwin, timer)	21s
build (stable, x86_64-apple-darwin, counter)	45s
build (stable, aarch64-apple-darwin, time)	21s
build (stable, aarch64-apple-darwin, timer)	21s
build (stable, aarch64-apple-darwin, counter)	59s
create-release	1s
	31m 30s

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